Dublin Dietitian

Pro Tips to Optimize Absorption of Nutrients in Your Digestive System

“You are what you eat” is a very famous saying . . . although, you may have heard the more accurate version of it: “You are what you eat and absorb.” Absorption is important because it’s possible to eat a variety of highly nutrient-dense foods but not get the full benefit from these nutrients simply because they pass right through you and are not absorbed from those foods.

You may literally be flushing your nutrition down the crapper.

If you experience any GI symptoms regularly – cramping, bloating, diarrhea, constipation – any indicate you may be struggling with nutrient absorption. Other signs could include fatigue, brain fog, difficulty putting on muscle or recovering from workouts, or floating oily stool.

Not absorbing nutrients is similar to not getting them in the first place. Nutrients can’t help your body if they never truly make it inside the cells and tissues to do the work they need to do. Not absorbing enough of all the essential nutrients can lead to health and fitness struggles if it leads to a deficiency (that’s why they’re called essential!) According to a study published in the journal Nutrients, researchers found that “Nearly one-third of the U.S. population is at risk of deficiency in at least one vitamin, or has anemia.” The top five most common nutrient deficiencies were for Vitamins B6, B12, C, and D, and the mineral iron. (LINK TO PAST BLOG POST)

Your digestive system is how your body takes the essential nutrients from your food, breaks them down into miniscule bits, and absorbs them so they can be used for growth, maintenance, energy, healing, and overall good health. For example, Vitamin A has to reach your eyes to prevent night blindness and Vitamin C has to make it to the skin to heal wounds. The same goes for iron for your blood and energy levels, and protein for your bones, muscles, and teeth. Before nutrients can get where they need to go, they first need to be extracted from the food and absorbed into your blood so that they can then be circulated to get where they need to go.

In this blog post we’ll go over some of top tips and strategies on how to make nutrients more absorbable. But first, why are some nutrients hard to absorb?

Why some nutrients are harder to absorb?

Everyone needs to get enough of all of the essential nutrients for good health. This includes macronutrients (a variety of proteins, quality carbohydrates, healthy fats) and micronutrients (e.g., vitamins and minerals). Absorption and digestion of nutrients can be tricky because there are so many different foods and nutrients, and so many factors that can affect our gut health.

Fun fact: How much of a nutrient is absorbed and can be used or stored in the body is called nutrient bioavailability. This describes how available the nutrient is for our biological use.

There are three main steps to digesting the food you eat:

breaking it down
absorbing the nutrients
eliminating the waste.

That’s why your digestive system provides a long, diverse journey for food to travel once it’s eaten. For example, your stomach is full of digestive juices (e.g., acid, enzymes) to break food into smaller pieces. Then, as your food starts moving through your small intestine, your liver and pancreas add alkaline bile (to neutralize the acid), as well as other enzymes to break down other components of food. Your small intestine is responsible for most—but not all—of the absorption of nutrients into your body. The final journey is through the large intestine that is home to your friendly gut microbes (helpful bacteria and other tiny microorganisms). These microbes can break down (or ferment) some of the toughest nutrients that have made it this far intact (some fibers). The large intestine also absorbs some nutrients and water.

Whatever nutrients don’t get absorbed—because they weren’t broken down small enough, or were complexed with anti-nutrients, or because the digestive tract itself couldn’t do its best work—is eliminated as waste. It’s natural and healthy to eliminate a lot of what you’ve eaten, but ideally the waste should have very little nutrition left in it. You want most of the essential nutrients to be absorbed so your body can use them for your best health.

Despite the diverse and complex processes that your body uses to absorb and digest as many nutrients from foods as possible, sometimes it can use some help. Some people have food intolerances or digestive issues that result in malabsorption of certain nutrients. Plus, there are some nutrient-nutrient interactions and anti-nutrients found in foods that can reduce your ability to absorb them.

The good news is that research shows there are some very interesting things that can increase nutrient bioavailability —without necessarily requiring supplements (though, in some cases, you do need to take it to that next level and supplement with enzymes and other items.) By eating certain nutrients together or apart – or certain foods cooked versus raw – you can enjoy the same foods, but in a more nutritionally efficient, bioavailable, way.

Strategies to get more nutrients from the same food

Here are some simple strategies to get more nutrition from the foods you enjoy.

Absorb more Vitamin C: Enjoy these foods fresh and raw

Vitamin C is one of the most common vitamin deficiencies in the U.S. Foods that are rich in Vitamin C include fruits and vegetables. Some of the highest sources of Vitamin C are bell peppers, citrus fruits (and their juices), kiwis, broccoli, and strawberries.

Vitamin C is an antioxidant that is water-soluble and destroyed by heat. This means that the Vitamin C levels are highest when the food is fresh and raw (or cooked as little as possible). To maximize the Vitamin C levels in your fruits and vegetables, try to eat them as fresh and raw as possible. If you enjoy them cooked, do so minimally by lightly steaming or microwaving them.

Vitamin C is also needed in order to absorb collagen, which is critical for bone, joint, and gut health. (read more in this past article here)

Get more iron: Enjoy iron-rich foods with—and without—these

Iron is the most common mineral deficiency in the U.S. Some of the most iron-rich foods are seafood, beans and lentils, liver, spinach, and tofu. Also, some breads and cereals are fortified with iron. But, not all iron-rich foods are equal. Iron is found in two different forms: heme (in animal-based foods) and non-heme (in plant-based foods).

Heme iron is more bioavailable and more easily absorbed than non-heme iron. This means that the iron in plants is more difficult to absorb, but there are some simple tips that you can use to absorb more.

Iron absorption can be enhanced when consumed with Vitamin C-rich foods and away from tannin-containing drinks like tea and coffee. This means, enjoy your beans, lentils, spinach, or tofu with a Vitamin C-rich food in the same meal. For example, add some bell peppers, orange wedges, or berries to your spinach salad. And enjoy your tea or coffee—not with, but—between your iron-rich meals.

Absorb more fat-soluble essential Vitamins A, D, E, and K

Vitamin A is found in liver, seafood, eggs, and fortified dairy. Pro-vitamin A (beta-carotene) is found in fruits and vegetables, especially orange ones like sweet potatoes and carrots, and dark green leafy ones like spinach and kale. Because of the way beta-carotene is stored in the plant cells, not all of it is as bioavailable as Vitamin A in animal-based foods. Unlike with Vitamin C, Vitamin A is fat-soluble and becomes more bioavailable when orange and dark green plant-based sources are cooked.

Vitamin D is essential for bone health because it promotes absorption of calcium and is needed by bone cells for growth and repair, Vitamin D also helps reduce inflammation and helps to regulate the immune system and carbohydrate metabolism. Known as the sunshine vitamin because your skin makes Vitamin D when exposed to UV light, Vitamin D is also naturally found in a few foods. These foods include seafood, mushrooms exposed to UV light, egg yolks, and some fortified dairy.

Vitamin E is an antioxidant vitamin that is necessary for protecting cells from oxidants to prevent or delay chronic diseases. Vitamin E is also essential for your immune system. Foods with high levels of Vitamin E include whole grains, nuts and seeds, and their butters and oils (e.g., wheat germ oil, sunflower oil, peanut butter).

Vitamin K comes in two forms: K1 is in dark green leafy vegetables, broccoli, soy, and herbs. Vitamin K2 is mostly made by bacteria, so it’s found in fermented foods like yogurt, cheese, and sauerkraut. Vitamin K is essential for proper blood clotting and bone metabolism.

These four fat-soluble vitamins can be fairly bioavailable on their own, but a simple tip can help enhance absorption even more: get enough healthy fat. This means cooking your vegetables with a bit of healthy oil or pairing them with a nutritious dip or dressing to help you absorb more of these essential fat-soluble vitamins.

Need some help with figuring out what to eat? These menus are all balanced with healthy nutrients as well as healthy fats in every meal!

Get more calcium: Be sure to have a regular supply of Vitamin D

The largest sources of calcium in the North American and European diets is from milk and dairy products. But as there are many reasons to have some caution with dairy products (quality, inflammation, intolerance, and more), I recommend keeping diary limited and look to mix in additional sources. You can also get calcium from fruits and vegetables (e.g., kale, spinach, broccoli), as well as mineral water, sesame seeds, and more (GET LIST). Some of the plant sources of calcium have lower bioavailability because they contain anti-nutrients like oxalate and phytic acid. The amount of calcium absorbed from these foods is increased with Vitamin D intake. While you don’t need to get Vitamin D in the same meal as a calcium-rich one, getting enough vitamin D every day is key—whether that means eating Vitamin D-rich foods with a bit of healthy fat or going outside in the sun.

Note: See the section above on fat-soluble vitamins for more information about Vitamin D.

Learn more about the risk of JUST taking calcium for bone health – be empowered to understand all nutrients you need by reading “Taking Only Calcium for Bones is Taking a Risk: Parts 1 and Part 2

Absorb more lycopene: Cooking tomatoes brings out this bioactive

Lycopene is similar to beta-carotene, but it is not considered an essential nutrient. Studies show that lycopene may help reduce risk of heart disease and some cancers like prostate cancer. Lycopene is a health-promoting antioxidant found red and dark green fruits and vegetables such as tomatoes, pink grapefruit, and watermelon. The main source of lycopene are cooked tomato products like ketchup, tomato juice, and pasta sauce.

Like Vitamin A above, cooking tomatoes and enjoying them with a little bit of healthy fat can improve your absorption of lycopene.

Bottom line

Healthy eating is a little bit more than consuming nutritious foods, it’s also about absorbing the nutrients from those foods so they can be used in your body. With a few simple tips, you can get more benefits when you enjoy the same nutritious foods you usually do.

Eating Vitamin C-rich foods fresh and raw, and cooking foods rich in fat-soluble vitamins can help you absorb more of those essential nutrients. Eating fat-soluble vitamins with a bit of healthy fat, iron-rich foods with some Vitamin C (but not tea or coffee), and calcium-rich foods with some Vitamin D can also enhance absorption.

And, to take it even one step further – if your gut is giving you issues, the perfect foods in the perfect balance may still not get digested and absorbed properly. If your gut is not functioning optimally, you are not absorbing optimally.

Do you have concerns about your digestion? Want to ensure you’re maximizing absorption of all the essential nutrients? Need some support in planning and making meals to get the most nutrition for you and your family? Reach out to see what may be the best help for you. Use a menu to get food ideas, or book a Complimentary Call with me today if you have chronic GI issues that need fixed.

Book a Complimentary Call Now

References

Bird, J. K., Murphy, R. A., Ciappio, E. D., & McBurney, M. I. (2017). Risk of Deficiency in Multiple Concurrent Micronutrients in Children and Adults in the United States. Nutrients, 9(7), 655. https://doi.org/10.3390/nu9070655
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537775/

Cleveland Clinic. (n.d.). Malabsorption. https://my.clevelandclinic.org/health/diseases/22722-malabsorption

Coe, S., & Spiro, A. (2022). Cooking at home to retain nutritional quality and minimise nutrient losses: A focus on vegetables, potatoes and pulses. Nutrition bulletin, 10.1111/nbu.12584. Advance online publication. https://doi.org/10.1111/nbu.12584
https://pubmed.ncbi.nlm.nih.gov/36299246/

Harvard T.H. Chan School of Public Health. (n.d.). Are anti-nutrients harmful? The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/anti-nutrients/

Melse-Boonstra A. (2020). Bioavailability of Micronutrients From Nutrient-Dense Whole Foods: Zooming in on Dairy, Vegetables, and Fruits. Frontiers in nutrition, 7, 101. https://doi.org/10.3389/fnut.2020.00101
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7393990/

National Institute of Diabetes and Digestive and Kidney Diseases. (n.d.). Your digestive system & how it works. https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works

National Institutes of Health. (2021, March 26). Vitamin C: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/

National Institutes of Health. (2021, March 26). Vitamin E: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/

National Institutes of Health. (2021, March 29). Vitamin K: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/

National Institutes of Health. (2021, June 15). Vitamin A and Carotenoids: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/

National Institutes of Health. (2022, April 5). Iron: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/

National Institutes of Health. (2022, August 12). Vitamin D: Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

Science Direct. (n.d.). Nutrient bioavailability. https://www.sciencedirect.com/topics/medicine-and-dentistry/nutrient-bioavailability

Story, E. N., Kopec, R. E., Schwartz, S. J., & Harris, G. K. (2010). An update on the health effects of tomato lycopene. Annual review of food science and technology, 1, 189–210. https://doi.org/10.1146/annurev.food.102308.124120

Holiday Hacks: 3 Time-Saving Kitchen Tips

The holidays are always a blur: holiday parties, school concerts, family gatherings, shopping, and vacations make us consider giving up on our health goals completely!

Instead, give yourself the gift of taking some shortcuts and holiday hacks to take some of the pressure off so you can relax and be merry [because nobody wants a scrooge in the kitchen].

Go Semi-Homemade

roasted chicken served on black ceramic plate

Clearly, we are very pro-cooking around here, but sometimes taking shortcuts can turn a potential take-out night into a total kitchen win. For example:

Grab a rotisserie chicken and incorporate it into soups or chilis so you can reap the benefits of high-quality protein without spending extra time cooking it. Shred the chicken and stuff lettuce leaves with a squeeze of lime for lunch.
Start with your favorite frozen pizza dough, then add your favorite jarred sauce and vegetable toppings plus a sprinkle of flavorful cheese to make it a meal!
Buy pre-chopped produce, especially those hard-to-manage vegetables (ahem, squash) that are more time-intensive to prepare. Toss with a tablespoon of olive oil and roast for a side dish or added to salads during the week.

Cook Once, Eat Twice

cook once eat all week - batch cooking tips.

Batch cooking (not quite the same as “bulk prepping”) is an efficient way to keep up with your healthy eating goals no matter what time of year. It essentially means cooking more than what you need at that moment so you can take advantage of having all of your cooking tools and gadgets out (read: it’s much more time efficient in the long run!). Not to be confused with leftovers or bulk prep – where you eat the exact same thing each day – batch cooking usually refers to one component that you can repurpose in a new way later. For instance:

Need rice or quinoa for your Monday night meal? Make a large batch so you can easily incorporate it in salads and grain bowls all week long.
Making hard-boiled eggs? It takes the same amount of time to make six as it does to make two. Enjoy as a snack, crumble into salads, or mash with some avocado.
Baking sweet potatoes? Make a few more than you need and you’ll have the base for an easy, customizable lunch ready to go. You can also purée or mash the flesh for baked goods and use in place of pumpkin in a recipe.
This cookbook would make an amazing Christmas gift for yourself! Or a gift to someone else. But in Cook Once, Eat All Week, the author lays out 26 weeks worth or batch cooking plans for you – so you due the main prep all at once, but mix it up a little each day to ensure your family is not getting bored with the exact same meal every day.

Sheet Pan and One Pot Meals

Raise your hand if your least favorite part of cooking is the clean up! We feel you! Make it easier on yourself by searching for one-dish meals to seriously cut down on time spent doing the dishes. Here are a few to get you started:

Create baking pockets by lining foil with parchment then crimping for perfectly roasted fish that stays juicy, never dry.
Roasting your favorite protein with seasonal produce is a tasty no-fuss way to incorporate a few servings of vegetables into a meal
Still haven’t learned how to use your Instant Pot? Now would be a good time! You can get frozen proteins to the table fast with a safe and simple pressure cooker. A simple 12-minute recipe: frozen protein [like chicken thighs] + favorite jarred tomato sauce + a jar of olives = yummy cacciatore that will have everyone running to the table for dinner. If you use plant-based protein, like dried chickpeas, just soak the dried beans overnight and be sure they are covered with fluid [jarred sauce + some broth] before cooking in Instant Pot.

Whatever you do to save time, remember that your nutrition mentality should not be “all or none.” Enjoy some treats, but balance it with healthy, fresh foods. Drink some water, take a few deep breaths, go for a crisp walk, and enjoy that holiday cookie party!

Be Well, Be Empowered

~Kate

Taking Only Calcium For Bones is Taking a Risk – Part 2

The misconception and dangerous recommendation to “take calcium for your arthritis/osteoporosis/bone health” was started in Part 1 of this topic.

If you missed it, check it out for some of the background. We went over

Some of the MANY nutrients that are needed for strong bones and joints
How they work together – how JUST taking calcium can actually increase your risk of calcification of your arteries, kidney stones, and cardiovascular disease.

So now that you know WHICH nutrients you need, let’s talk about where to get them!

I am a fan of “food first,” but I’ve learned enough to realize that “food only” doesn’t always cut it – especially when getting into medical issues where you need therapeutic doses. Those doses can go far above the RDA (safely, with a heath professional monitoring you.) The RDAs are essentially bare minimums that were set for a healthy person just to avoid illness. It is not the amount needed for someone with a current health issue needing to rebuild, nor is it related to an optimal amount. But that doesn’t mean go wildly overboard either – too much of a good thing can be dangerous as well.

Focus on foods first, supplement with guidance, and TEST, DON’T GUESS! Ideally, you would do a micronutrient panel at least annually to ensure your stores are where they are needed.

3: IN THE RIGHT FORM – SAFE & ABSORBABLE

Food should always come first, but when needed, discuss supplements with your nutrition professional. I have had hours of additional training on supplements, and what it taught me is that even dietetic undergrads are lacking a deeper medical understanding – let alone doctors who get VERY little nutrition training, if any! Find someone who goes beyond just the minimum classwork.

Most supplements come in a variety of forms, and this makes a difference in quality and safety. (You can watch/listen to this Gut Check Podcast episode on supplements, and why “you get what you pay for,” so be mindful.)

Calcium:

Don’t be fooled – dairy is not the only option! It is a good source of calcium but I have my hesitations with dairy. It can be a part of a healthy diet, but if you are already dealing with an inflammatory condition (such as arthritis, IBS, gastritis, etc), dairy is commonly inflammatory for many people. So don’t feel like you have to force the diary. Many people find their symptoms ease with reduced dairy intake.

Some food sources:

¼ cup sesame seeds (think tahini!): 351mg
3.2oz sardines: 347mg
1 cup yogurt: 296mg
1 cup (8oz) cow milk: 275mg
1 cup collard greens: 270mg
1 cup spinach: 245mg
1oz cheese: 204mg
1 cup mustard, beet, or turnip greens: 165-200mg
1 cup Swiss chard: 100mg
1oz almonds: 76mg
1 cup cabbage, broccoli, or Brussels sprouts: 60mg
1 orange: 50-90mg based on size
4oz raisins or prunes: 45mg
Beans and lentils also have some, in varying amounts

SUPPLEMENTS

There are different types of calcium, and often supplement companies will cut corners on cost by using cheaper versions.

Calcium from things like oyster shells, coral, or limestone often have contaminants, and one meta-analysis determined it may be behind heart attack risks.

Calcium carbonate is very affordable – but hard to digest, it needs a lot of acid. And guess what Tums are made from! Calcium carbonate, with the entire goal being to neutralize your stomach acid levels and NOT to be absorbed. And of course if it is only supplying calcium, we’re back to #1 and #2: ALL NUTRIENTS, IN BALANCE.

Also if your stomach acid is blocked, you will have more trouble digesting and absorbing protein and magnesium, which also takes us back to #1 – ALL needed nutrients. So Tums and antacids backfire on this, and long-term use of PPI’s and heartburn meds often create these same issues. (More on the role of medications and gut health in this Gut Check Podcast)

Calcium supplements can also reduce the absorption of iron and zinc, as well as impair the absorption of some antibiotics; and sometimes can cause constipation.

If you do need to supplement, calcium citrate or a chelate tends to be the safest form for all. I use food as my main source, but do have calcium chelate in small amounts in my multivitamin.

Protein

I won’t get down into the details here about amounts, timing, or the plant-based vs animal-based details – that will be in a future course. But here are some common food sources:

4oz Tuna, Chicken, or Turkey: 35g avg
4oz Beef, salmon, lamb, or shrimp: 25g avg
1 cup beans, peas, legumes: 15g avg
½ cup oats: 14g
1 oz nuts and seeds: 9g avg
1 cup yogurt: 8g
1 egg: 7g
1 cup collard greens: 5g
1 cup broccoli: 4g
1 cup cabbage, cauliflower, or mushrooms: 2g avg

SUPPLEMENTS:

There can be a lot to be said about breaking down types of protein powders and when to use them – whey, casein, whey isolate, collagen, vegan, etc. But for now, we will keep it general. That will be a post for another time.

Aim for quality, to ensure you are getting contaminant-free. Consumer Reports routinely finds protein powders that have less protein (and more carbohydrates!) than the label states; or some have been found contaminated with lead or other toxins. Grass-fed New Zealand cows are best for whey or collagen proteins, as they have better regulation on the legal definition of “grass fed” that what the US allows.

Maintenance doses of collagen range from 10-20g; therapeutic levels of collagen range from 30-50g. Total protein needs range drastically based on personalization.

I use PropelloLife collagen before workouts and rehab/PT, and their whey protein after strength training. (you can get 10% off using this link and promocode DUBLINDIETITIAN. I make no money, I just support them)

VITAMIN D

Vitamin D comes in two main forms: D2 (“Ergocalciferol”) comes mostly from plants that can synthesize it with the UVB rays of the sun, and D3 (“cholecalciferol”) which is made by the cholesterol in your skin when exposed to the UVB rays (hence, Vitamin D often being called “the sunshine vitamin.”

Do note briefly – we DO need cholesterol! If your doctor has you on statins and is driving your number below 160, we begin to see more issues, including the inability to do the creation of vitamin D by your skin if you don’t have the cholesterol as the precursor to do so. This in turn causes more mood issues and depression, since it’s also a precursor to seratonin.

Some food sources:

4oz Salmon (with skin): 511 IU
3.2oz sardines (with skin): 175 IU
8oz Cow Milk (fortified with Vit D): 124 IU
4oz Tuna: 93 IU
1 egg: 44 IU
1 cup shiitake mushrooms: 41 IU

SUPPLEMENTS:

It’s best to know your lab levels – most doctors can test for you; or we can order a lab together. Too little supplementation, and you can continue to deal with poor absorption, inflammation, weaker bones, etc. Too high, and Vit D overload can be problematic as well. In general, a daily dose of 400-1,000 IU is common for maintenance. I use Vitamin D liquid drops during the winter months, in addition to my Thorne Elite Multivitamin. I try to get daily sunshine when I can.

Vitamin K

There are 3 forms of Vitamin K to be aware of: K₁ most commonly found in plants; K₂-MK-4 found in animal products; and K₂-MK-7 found in fermented foods. It’s not entirely known which forms are best for what specific role, so it’s good to get some from each area.

Some food sources:

1 cup kale: 1062 mcg
1 cup spinach: 888 mcg
1 cup mustard greens: 830 mcg
1 cup collard greens: 773 mcg
1 cup beet greens: 697 mcg
1 cup Swiss chard: 573 mcg
1 cup broccoli: 220 mcg
1 cup asparagus: 91 mcg
1 cup green peas: 35 mcg
1 cup avocado: 32 mcg
1 kiwi fruit: 28 mcg
1 cup blueberries: 29 mcg
1 cup carrots: 16 mcg
Small amounts in meat, dairy, eggs, an fermented items

Note: if you are on a blood thinner, you need to discuss vitamin K intake with your dietitian or doctor since Vitamin K helps blood clot. The old recommendation to avoid Vit K is out – but you do need to be CONSISTENT with your Vitamin K intake, so that the blood thinner dose can be modified as appropriate to match your intake.

SUPPLEMENTS:

I do not do Vit K supplements alone unless we’ve done a full nutrient lab panel and know a precise amount. Otherwise, I use food, and then the additional amounts as a part of the Thorne Elite Multivitamin or with a BoneStregnth supplement.

MAGNESIUM

Some food sources:

1 oz pumpkin seeds: 190 mg
1 cup quinoa: 155 mg
1 cup Swiss chard or spinach: 150mg
¼ cup sesame seeds: 126 mg
1 cup black beans: 120 mg
1 oz cashews or sunflower seeds: 115 mg avg
1 cup brown rice, pinto beans, or lima beans: 83 mg avg
1 oz almonds: 61 mg
2 Tbs flaxseeds: 55 mg
1 cup collard greens, broccoli, or Brussels: 35mg avg
1 cup raspberries: 27 mg
1 cup tomatoes: 20 mg

SUPPLEMENTS:

Here is another area where form is critical. Magnesium can come in many different forms, and they and they have different absorption abilities, safety factors, and secondary uses.

Some examples of different types of magnesium with notes:

Magnesium Oxide: cheap, but poorly absorbed and can cause stomach upset
Magnesium hydroxide can help with constipation
Magnesium Glycinate: can help with detox in people who are genetically prone to struggle
Magnesium Citrate: acidic, which can help with a body’s pH balance if appropriate
Magnesium Taurate: can be calming
Magnesium Aspartate or Mg Glutamate: excitatory, so can help with chronic fatigue but caution with ADHD, anxiety, autism
Magnesium Chloride: better for topical application (ie: lotions to help with muscle spasm, restless leg, fibromyalgia)
Magnesium Sulfate: Epsom salts, good for muscles and fibro since it bypasses the gut and goes directly into the muscles, but may cause looser stool in some

Magnesium (Mg) is a larger mineral than many others, so it is hard to fit enough of it into a multivitamin without making them excessively large. Even with the Thorne Elite Multivitamin that I use (which has a Mg Chelate), I still take an additional magnesium supplement on heavy training days. I also use a Mg Chloride lotion directly on muscles after multi-hour events to help replenish muscle stores.

So that all certainly shows you it is so much more than just
dairy for calcium for your bones!

[See list of supplements I discuss and use here]

4: WITH A SUPPORTIVE LIFESTYLE AROUND IT

A quick tangent with some anatomy and physiology terms…

There are large cells on the surface of your bone called osteoblasts and osteoclasts. OsteoBlasts help Build bone by synthesizing and mineralizing it. On the other hand, osteoClasts Crush down bone. Ok, not literally crush it, but for the mnemonic, it helps. Osteoclasts break down the bone, causing the minerals to be released into the blood stream. This has its purpose, so it should happen in balance, but there are things that accelerate the osteoclast’s actions – meaning, it erodes the bone more quickly than the osteoblasts can rebuild it. (Examine: bones)

INFLAMMTION: Inflammation issues accelerates osteoclast behavior – and any issues with our basic lifestyle increase inflammation. So control inflammation with the anti-inflammatory food list, proper sleep, hydration, deep breathing, appropriate exercise, removal of toxic burden. I often harp on and on about the damage of excess inflammation and its role in nearly all chronic health issues – and bone health is no different. Chronic health issues are caused by – and cyclically continue to cause – inflammation. So having any chronic inflammatory-based condition can also increase your risk of bone loss.

HORMONES: Estrogen also plays a protective role, which is why more osteoporosis is seen after menopause. there can be risks for younger female athletes who lose their period cycle if they are under fueling and/or over training ; or anyone on hormone treatment (birth control, or otherwise) if it skews the standard ratios of sex hormones.

EXERCISE: Weight training – specifically, dynamic movements versus static – increases mechanical loading, which is a stimulus for increasing bone mass. If you are trying to strengthen bones or heal knee joints, avoiding weight on it can delay the healing. Likewise, low lean body mass exacerbates bone loss. But be mindful – “too much of a good thing” is real with exercise. If inflammation is an issue, overtraining is a risk factor. Many people spend ample time in high zone/high intensity training which does work on anaerobic factors and muscle training; but do not neglect the low zone/aerobic training which is less inflammatory in nature.

CALORIC REDUCTION: If you are reducing calories, you may lack some of the needed nutrients as discussed above. Be very diligent in getting all that you need with the reduced calories. Often when an injury is being addressed, you may need to INCREASE total caloric intake, because your body needs extra energy to heal and recover.

GENETICS: And, yes, sometimes genetics can make to more of an uphill battle as well. While genes are not a guarantee of issues, they can increase risk or susceptibility. Some genetic variants increase natural inflammation, reduce ability to detox out environmental toxic burden, slow bone formation, alter sex hormones, and more.

SUMMARY:

Did you catch all of that? Take some time to review – it is a lot.

Overall, my hope is you take away that bones are complex and trying to oversimplify it by saying “just take some calcium” is an ignorant recommendation that is risky and out of date.

You need to nourish your bones with the right foods and minerals and protect your bones with a healthy lifestyle.

LEVEL 1:

Use the 7 Day Challenge and starting food list to begin the process of reducing inflammation
Focus on the above recommended foods to support bone nutrients
Ensure adequate hydration, sleep, and stress management
Include weight bearing exercises and dynamic movements in your routines (only do moves you can do without joint/bone pain!)

LEVEL 2:

Reach out to discuss potential supplements to add
Get the Micronutrient Panel to see how everything looks, and personalize your food and supplements from there
Get the MRT test if you need a bigger reversal of symptoms, inflammation, and issues

Dealing with arthritis? Click here to let me know if you’d like to be kept up to date on the upcoming Arthritis Reversal pilot group, or other upcoming courses!

SOURCES:

Allen, Susan. “Certificate of Training in Integrative and Functional Medical Nutrition Therapy.” Dietary Supplements. Vitamin D and Minerals. Next Level Functional Nutrition. 2017/2019.

The George Mateljan Foundation. World’s Healthiest Foods, whfoods.com. Accessed Nov 9, 2022.

Goolsby MA, Boniquit N. Bone Health in Athletes. Sports Health. 2017 Mar/Apr;9(2):108-117. doi: 10.1177/1941738116677732. Epub 2016 Nov 30. PMID: 27821574; PMCID: PMC5349390.; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5349390/pdf/10.1177_1941738116677732.pdf

Hull, Michael MSc; Brown, Wyatt. Sicart, Pierre-Alexandre PhD (Ed). Bone Health Supplement Guide. Examine. Sept 2020.

Lanham-New, Susan A. “Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment.” The Proceedings of the Nutrition Society vol. 67,2 (2008): 163-76. doi:10.1017/S0029665108007003; https://pubmed.ncbi.nlm.nih.gov/18412990/

Palermo, Andrea et al. “Vitamin K and osteoporosis: Myth or reality?.” Metabolism: clinical and experimental vol. 70 (2017): 57-71. doi:10.1016/j.metabol.2017.01.032; https://pubmed.ncbi.nlm.nih.gov/28403946/

“Time for More Vitamin D.” Harvard Health Publishing; Harvard Medical School. September 1, 2008. https://www.health.harvard.edu/staying-healthy/time-for-more-vitamin-d. Accessed November 7^th, 2022.

“Vitamin K.” Harvard University, The Nutrition Source. Harvard University, T.H. Chan. https://www.hsph.harvard.edu/nutritionsource/vitamin-k/. Accessed November 8, 2022.

Taking Only Calcium For Bones is Taking a Risk – Part 1

medical imaging of an injury on the hand

Bones are more than calcium! If you are looking to have strong, healthy bones, you need to be aware of all components. When you AREN’T, you can actually make things worse. If you are taking a calcium supplement without addressing the other aspects, you may increase your risk of kidney stones, arterial plaque, cardiovascular disease, and more.

When it comes to bone health, you need to be aware of:

ALL needed nutrients
In balance
In the right form
With a supportive lifestyle around it

Over the next few posts, we will break each of these down and dig into the truth about bone health.

Contrary to popular belief, our bones are not static. They are not “frozen in form” like a plastic Halloween skeleton. They are dynamic, growing, shifting, and forming.

When we break a bone, bone cells grow back slowly and the fracture or break heals. Your bones are alive! And like the rest of your body, your bones want to heal – and they do, when we know how to properly care for them, and feed them.

So in today’s post, we will start with a review of Sections #1 and #2 — all the needed nutrients, and how they work in tandem.

1: ALL NEEDED NUTRIENTS

Healthy bones do require calcium, but you also need magnesium, phosphorous, Vitamin D, Vitamin K2, collagen, and glycoproteins.

Calcium

The crux of this article! When it comes to bone health, supplementing calcium is nearly the LEAST important of all aspects – it’s not NOT important, but it is lower on the priority list. We can blame dairy lobbyists for that massive marketing push!

The scary truth is that supplementing with calcium alone comes with HUGE RISKS, without any of the compounding factors we’re discussing here.

Too much calcium can lead to hypercalcemia. When we have too much free-floating calcium, it can be downright dangerous! – which will be elaborated in section #2: IN BALANCE WITH EACH OTHER. Some symptoms of hypercalcemia include kidney stones, constipation, nausea, loss of appetite, bradycardia, cardiac arrhythmias, cardiovascular disease, hypertension, fatigue, memory loss, depression, anxiety, coma, and even death.

Yes, calcium is one of the major mineral components of bone, and deficiency can lead to osteopenia and osteoporosis. If you are looking to heal bone damage from arthritis, calcium is an important piece of the puzzle – along with everything else discussed here. But we want APPROPRIATE levels in the right balances. Most of this can come through food. Supplement mindfully if needed.

**Food Sources and Supplement notes for each nutrient will be listed under #3: IN THE RIGHT FORMS – to be published later this month

Protein

By volume, your bones are 50% protein, the bulk of that as Type 1 Collagen. So be sure to get enough protein in general – that can range from 0.8-2.2g/kg based on your heigh, age, weight, gender, health status, and goals. But, most studies see that at least 1.4g/kg/day with a minimum of 90g/day had a positive effect on bone density. (Join the wait-list for the Personalized Nutrition Program I’m working on, to help determine your exact needs)

There was an old study done that showed a higher intake of protein lead to a higher level of calcium in the urine, and it was assumed that meant the high protein was causing more bone turnover or breakdown. We know now that hypothesis was misleading. First, most of those studies used dairy protein – which may have more of an inflammatory issue. So once other protein sources were included, and compared, we found that protein actually helps with the calcium absorption, so protein intake helps with healthy bones.

A research review from Examine explains it nicely this way: “What happens is that when you ingest more protein, you absorb more of the calcium in your food, so less calcium ends up in your feces. Later, your body gets rid of the calcium it doesn’t need, so more calcium ends up in your urine, but not as much as would have otherwise ended in your feces. Therefore, an increase in protein intake leads to an overall decrease in calcium excretion, which points to an increase in calcium retention. High-protein diets also raise your insulin-like growth factor-1 (IGF-1) which promotes notable bone growth. All in all, current evidence suggests that protein’s effect on bones is either neutral or beneficial.

Vitamin D

Low vitamin D levels are incredibly common. “Except during the summer months, the skin makes little if any vitamin D from the sun at latitudes above 37 degrees north (in the United States, the shaded region in the map) or below 37 degrees south of the equator. People who live in these areas are at relatively greater risk for vitamin D deficiency.” (Harvard University)

And, as we will discuss more in section #4 LIFESTYLE – increased inflammation exacerbates bone breakdown. It is critical for many reasons to keep Vitamin D levels in a healthy range.

When it comes to bone health, Vitamin D is needed to help your small intestines absorb the calcium you ingest.

Vitamin K

Vitamin K is needed to help get calcium from your blood stream and into the bones, help regulate bone mineralization, help accumulate collagen, inhibit the cells that breakdown bone, and stimulate the cells that build bone.

Magnesium

Magnesium is another major mineral component of the bone matrix; and over 50% of people are low in magnesium. If you are stressed, or inflamed, that burns through more magnesium – and inflammation also breaks down bone more quickly. And, like protein, if you have some GI issues, you will likely struggle to absorb enough Magnesium. So address gut health!

Our sweat is another way people lose a lot of magnesium – it is one of the electrolytes lost. Therefore high-training athletes can be at risk. It is common to hear people have stiff muscles or muscle cramps if they are low in magnesium.

Additional Supportive Nutrients:

Strontium, Silica, and Vanadium — but as they are smaller portions, and this post has gotten long enough, we’ll leave it off here for now.

2: IN BALANCE WITH EACH OTHER

All of those needed nutrients work together, and if out of balance, can imbalance health.

Vitamin D helps your intestines absorb more of the calcium – having the calcium sit in your stomach doesn’t do anyone any good. You need the vitamin D to absorb it and get it into your blood stream.

But, we don’t just want it floating around there doing laps through your circulatory system!

If you take in more calcium than your body can shuttle into your bones, you then get free calcium in your body. High Free Calcium Excess is seen with chronic inflammation, arthritis, and especially heart disease because that free floating calcium can calcify in your arteries. It’s very much like plaque on your teeth, but in your arteries.

Instead, you need Vitamin K to help transport the calcium from blood to the bone and drive it in, where it then can help.

So if you take in all this calcium, but don’t have enough of the other nutrients to get it into the bone tissue, then you may be at an increased risk for the health issues mentioned before.

Your bone matrix is a beautifully complex web of all of these nutrients, so all are needed in your nutrition plan, with your body’s ability to properly digest, break down, absorb, and utilize them.

Stay tuned for Sections #3 and 4: Food sources, and important things to know about supplements; and how lifestyle factors in as well.

SOURCES:

Allen, Susan. “Certificate of Training in Integrative and Functional Medical Nutrition Therapy.” Dietary Supplements. Vitamin D and Minerals. Next Level Functional Nutrition. 2017/2019.

Hull, Michael MSc; Brown, Wyatt. Sicart, Pierre-Alexandre PhD (Ed). Bone Health Supplement Guide. Examine. Sept 2020.

“Vitamin K.” Harvard University, The Nutrition Source. Harvard University, T.H. Chan. https://www.hsph.harvard.edu/nutritionsource/vitamin-k/. Accessed November 8, 2022.

“Vitamin K Fact Sheet for Health Professionals.” National Institutes of Health, Office of Dietary Supplements. U.S. Department of Health & Human Services. https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/#h3. Accessed November 8, 2022.

Are You Lacking One of These Top 5 Fitness Nutrients?

man and woman at the gym doing planks while looking at each other and smiling

It’s proven: 31% of people in the United States are at risk for a deficiency in at least one vitamin or mineral essential for good health. It may be hard to imagine that we don’t get enough nutrition when we see an abundance of food available 24/7, but it’s true. A recent study showed the top five nutrients many of us need more of.

Should you be concerned about being low in one or two vitamins or minerals? In a word, yes. That’s because vitamins and minerals are essential for optimal health. Being low may not cause immediate symptoms, but it puts you at risk for many serious diseases that can affect your brain, heart, blood, immune system, metabolism, bones, mental health, and more.

Nutrients are key pieces your body needs to maintain all of your systems in good working order. Missing just one or two pieces can throw off the delicate balance you need to be healthy and feel great. That’s because most nutrients don’t have just one vital role to play within the body, they play many, many vital roles.

How would you even know if you’re at risk for a nutrient deficiency? It’s not always obvious. Sometimes symptoms aren’t felt for a long time and sometimes they’re very vague and non-specific. For example, fatigue, irritability, aches and pains, decreased immune function, and heart palpitations can be signs of many things — including a nutrient deficiency. This article goes over the five most commonly deficient nutrients, some of the more obvious symptoms, and foods that are high in each so you can get enough.

Sometimes, just eating a healthy diet isn’t enough! Stress, certain medications, health issues, and more can burn through excess nutrients. High levels of athletic training increase body needs. And, if you ever experience bloat, heart burn, or other GI issues, you may lack optimal digestion and you may not be able to absorb these vital vitamins from your food properly.

So read on, and eat up!

1) Vitamin B6 – elevates energy and metabolism

low angle photography of man jumping - vitamin B6 helps with energy. — B vitamins help with energy

The number one most common nutrient deficiency in the US was Vitamin B6. This vitamin is important for your blood, brain, and metabolism. Vitamin B6 helps the formation of hemoglobin in the blood (the part that carries oxygen around). It also helps to maintain normal levels of homocysteine (high levels of homocysteine are linked with heart disease). In addition, this vitamin plays an important role in the production of neurotransmitters (chemical messengers allowing nerve cells to communicate with each other). Not to mention the fact that it’s also involved with over 100 enzyme reactions in the body, mostly for metabolism.

Some of the main symptoms of a serious deficiency in Vitamin B6 are depression, confusion, convulsions, and a type of anemia called “microcytic” anemia. Symptoms of a less serious deficiency are no less serious. They include increased risks for heart disease and Alzheimer’s. These wide-ranging health effects are why Vitamin B6 is so essential for health.

Vitamin B6 is found in all food groups. Vitamin B6 is found in high quantities in potatoes, non-citrus fruits (e.g., bananas), and various animal-based foods such as poultry, fish, and organ meats.

2) Vitamin B12 – needed for nerves, brain, and blood

Vitamin B12 is critical for the healthy nerves, including brain neurons

Like Vitamin B6, Vitamin B12 is also very important for your blood and brain. It is needed for the creation of healthy red blood cells and the formation of the outer coating of nerve cells (myelin) which is very important for their optimal functioning.

Vitamin B12 can be a bit difficult to absorb from your food. To improve absorption, it’s important to have adequate acid and digestive enzymes in the stomach. This is because the vitamin is very strongly bound to the proteins in food, and stomach acid and enzymes help to break those bonds and free the vitamin so your body can take it in.

Having a Vitamin B12 deficiency can be caused by a type of anemia called “pernicious” anemia. Pernicious anemia is an autoimmune disease that affects the stomach and reduces its ability to absorb Vitamin B12. A deficiency in Vitamin B12, in turn, can then lead to a different type of anemia called “megaloblastic” anemia. Low levels of Vitamin B12 can also cause neurological damage (due to impaired myelination of nerve cells).

Vitamin B12 isn’t naturally present in most plant-based foods, except it is found in some nutritional yeast products. It is naturally found in dairy, eggs, fish, poultry and meat and is particularly high in clams, beef liver, trout, and salmon.

If you are consuming Vitamin B12 supplements, your levels of stomach acid and digestive enzymes aren’t as critical as they are for the absorption of the vitamin directly from foods. This is because when adding Vitamin B12 to foods and supplements, it’s not tightly bound to their proteins and this makes it much more easily absorbed.

3) Vitamin C – critical for collagen and joints

a person touching his knees - Vitamin C helps you absorb collagen, critical for healing and supporting healthy joints and tendons — Vitamin C helps you absorb collagen, critical for healing and supporting healthy joints and tendons

Vitamin C is important for wound healing (via a protein called collagen; read more on vitamin C, collagen, and connective tissue health here), the production of neurotransmitters, metabolism, and the proper functioning of the immune system. Vitamin C also acts as an antioxidant to reduce the damage caused by free radicals that can worsen several diseases such as certain cancers and heart disease. Vitamin C also helps your body absorb the essential mineral iron, which is one of the top five nutrient deficiencies also included later in this article.

You can get Vitamin C from many fruits and vegetables. Ones particularly high in Vitamin C include bell peppers, oranges, and orange juice. Other good sources of the vitamin include kiwifruit, broccoli, strawberries, Brussels sprouts, tomato juice, cantaloupe, cabbage, and cauliflower. Vitamin C is not naturally present in grains.

When choosing foods for Vitamin C, choose the freshest options because levels of the vitamin naturally reduce over time the longer the food is stored. Try, as much as possible, to eat Vitamin C-rich foods raw. If you do cook them, then choose steaming instead of prolonged boiling because the vitamin is destroyed by heat and is water-soluble.

4) Vitamin D – bones and bright smiles!

Vitamin D, the sunshine vitamin - strong bones and teeth, anti-inflammatory, and mood boosting! — Vitamin D, the sunshine vitamin – strong bones and teeth, anti-inflammatory, and mood boosting!

Vitamin D, also known as the “sunshine vitamin,” is very important for your bones. It promotes the absorption of the mineral calcium. When your body has enough calcium, it can maintain normal bone mineralization and prevent problems in the muscles that lead to cramps and spasms. Getting enough Vitamin D and calcium can also help protect against osteoporosis (ensuring your stomach is properly digesting and absorbing – heart burn can indicate an inability to properly digest these and other nutrients.) In addition to all of these bone and muscle impacts, Vitamin D helps to reduce inflammation and modulate both immune function and sugar metabolism.

Without enough Vitamin D, bones can become thin, brittle, or misshapen. Vitamin D prevents these issues known as rickets (in children) and osteomalacia (in adults).

Your skin makes Vitamin D when it’s exposed to the ultraviolet rays of the sun and very few foods naturally contain it. The few Vitamin D-rich foods include fatty fish and fish liver oils (e.g., salmon, trout, cod liver oil). Other foods that naturally contain small amounts of Vitamin D include egg yolks, beef liver, and cheddar cheese. Some mushrooms can contain Vitamin D—particularly those exposed to UV light.

Most of the dietary Vitamin D that people in the US get is from fortified foods and beverages. These include some dairy products (mainly milk), certain plant milks (e.g., soy, almond, or oat milks), various breakfast cereals, and a few types of orange juice..

If you need to supplement with Vitamin D, it’s best to get your labs tested to see where you are at so you know how to properly dose.

5) Iron – oxygen, joints, and muscles

grilled food on black cooking pot - Iron is critical for health. It supports healthy blood and oxygen — Iron is critical for health. It supports healthy blood and oxygen

Iron is a mineral essential for healthy blood so that it can transport vital oxygen throughout your body every second of every day. This happens via a compound in your red blood cells called “hemoglobin.” Iron also supports your muscles (like Vitamin D) and your connective tissue (like Vitamin C). Having adequate iron is necessary for physical growth, neurological development, hormone production, and the function of your cells.

A deficiency in iron is commonly known as “anemia.” Menstruating women tend to be lower in iron simply because of their regular loss of blood.

Most iron in the body is in the blood, but there is some stored in the liver, spleen, bone marrow, and muscles. This is why iron deficiency progresses slowly from depleting your stores (mild iron deficiency), to reducing the number of red blood cells (marginal iron deficiency), before you get to full-out iron deficiency anemia.

Iron is naturally found in many foods in one of two forms: heme and nonheme. Animal-based foods contain the more absorbable heme form. Plant-based foods naturally contain nonheme iron. This is where Vitamin C comes in. Vitamin C helps your body absorb the nonheme iron from plants, which is why, if plants are a main source of iron in your diet, it’s important to combine iron-rich plants with Vitamin C-rich plants in the same meal.

Some of the best sources of iron include oysters, white beans, dark chocolate, beef liver, lentils, spinach, and tofu.

[If you want to follow a plant-based meal plan, consider subscribing to this vegan menu plan to ensure you’re getting a good balance of needed nutrients]

Bottom line…

Up to one-third of people in the US are at risk for at least one nutrient deficiency. Most commonly, that deficient nutrient is Vitamin B6, but there are also many people deficient in vitamins B12, C, and D, as well as the mineral iron. Vitamins and minerals are essential nutrients because everybody needs them on a regular basis for good health. Lacking in any one nutrient can have far-reaching consequences.

set of tasty fresh vegetables and herbs with empty clipboard

Eating a nutrient-rich diet with a variety of foods can help everyone achieve their health and nutrition goals. If you need some help with figuring that out, you can find a variety of dietitian-approved menus here! Whether you want general whole foods, gluten-free, gluten- and dairy-free, Low FODMAPS, low histamine, or more, check out the options.

To support a fairly whole-food based eating style, my favorite multivitamin to help as a “safety net” of nutrition is the Thorne Elite – especially effective for active people to support workout recovery; those who don’t feel rested after sleep; and those dealing with a lot of stress. You can check out Thorne Elite, as well as other foundational supplements here, and sign up for `15% off.

If you want to know exactly what your nutritional stores are, and how your labs stack up, we can set up a time to run a Micronutrient Panel for you and see exactly where you’re at. B Vitamins, antioxidants, amino acids, glucose metabolism, Vitamins A, D, E, K, and more. We’ll review your foods and supplements, and create a plan to keep you at optimal levels.

Feeling “off” or having symptoms that concern you? Book an appointment with me discuss your goals and struggles, and we can get a game plan in place for you.

From where you are to where you want to go, we can create a plan.

Book a Complimentary Call Now!

References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537775/

National Institutes of Health Office of Dietary Supplements. (2020, February 28). Iron fact sheet for health professionals.

https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/

National Institutes of Health Office of Dietary Supplements. (2020, February 4). Vitamin B6 fact sheet for health professionals.

https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/

National Institutes of Health Office of Dietary Supplements. (2020, March 30). Vitamin B12 fact sheet for health professionals.

https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/

National Institutes of Health Office of Dietary Supplements. (2020, February 27). Vitamin C fact sheet for health professionals.

https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/

National Institutes of Health Office of Dietary Supplements. (2020, October 9). Vitamin D fact sheet for health professionals.

https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/