In the first three articles in this series, we discussed which foods to eat and which foods to avoid. In this article we’re going to talk about when to supplement and how to do it wisely. We’ve got a lot of material to cover, so you might want to grab a cup of tea and get comfortable!

There are three principles to supplementing wisely:

• Get nutrients from food whenever possible.
• Take nutrients in their naturally occurring form whenever possible.
• Be selective with your supplementation.

Get nutrients from food whenever possible

Humans are adapted to getting nutrients from whole foods. Most nutrients require enzymes, synergistic co-factors and organic mineral-activators to be properly absorbed. While these are naturally present in foods, they are often not included in synthetic vitamins with isolated nutrients.

In a paper published in the American Journal of Clinical Nutrition called Food Synergy: An Operational Concept For Understanding Nutrition emphasizing the importance of obtaining nutrients from whole foods, the authors concluded:

A person or animal eating a diet consisting solely of purified nutrients in their Dietary Reference Intake amounts, without benefit of the coordination inherent in food, may not thrive and probably would not have optimal health. This review argues for the primacy of food over supplements in meeting nutritional requirements of the population.

They cautioned against the risk of reductionist thinking, which is common in conventional medicine and nutritional supplementation. Instead, they urge us to consider the importance of what they call “food synergy”:

The concept of food synergy is based on the proposition that the interrelations between constituents in foods are significant. This significance is dependent on the balance between constituents within the food, how well the constituents survive digestion, and the extent to which they appear biologically active at the cellular level.

They go on to provide evidence that whole foods are more effective than supplements in meeting nutrient needs:

• Tomato consumption has a greater effect on human prostrate tissue than an equivalent amount of lycopene.
• Whole pomegranates and broccoli had greater antiproliferative and in vitro chemical effects than did some of their individual constituents.
• Free radicals were reduced by consumption of brassica vegetables, independent of micronutrient mix.

In short: get nutrients from food, not supplements, whenever you can.

Take nutrients in their naturally occurring form whenever possible

Synthetic, isolated nutrients don’t always have the same effect on the body. It matters whether the nutrients have been produced by technologic or biological processes, because industrial processing sometimes creates an entirely new compound with different physiological actions. Trans fat produced in ruminant animals (such as conjugated linoleic acids in dairy products) are beneficial to health, whereas trans fats produced in the processing of industrial seed oils are highly toxic.

Folic acid is another example. The naturally occurring form of folate is not folic acid, a compound not normally found in food or nature, but tetrahydrofolate. While folic acid can be converted into folate, that conversion is poor in humans. It’s also important to note that unlike natural folate, folic acid does not cross the placenta. This is significant because folate is a crucial nutrient for pregnancy, and while folic acid can prevent neural tube defects it doesn’t have the other beneficial effects of folate. What’s more, several studies have shown that folic acid – but not natural folate – increases cancer risk. Unfortunately, folic acid is what’s often used in multivitamins, because it’s significantly cheaper than natural folate.

Be selective with your supplementation.

Multivitamins have become increasingly popular: half of Americans currently take one. But is this a good idea? Most studies show that multivitamins either provide no benefit, or may even cause harm. A study in the Archives of Internal Medicine showed that multivitamins have little to no influence on the risk of common cancers, CVD or total mortality in postmenopausal women. A now infamous meta-analysis in the Journal of American Medical Association, which looked at over 68 trials with 230,000 pooled participants, found that treatment with synthetic beta carotene, vitamin A and vitamin E may increase mortality.

The problem with multivitamins is that they contain too little of beneficial nutrients like magnesium, vitamin D and vitamin K2, and too much of potentially toxic nutrients like folic acid, calcium, iron and vitamin E. This means that multivitamins can actually cause nutrient imbalances that contribute to disease. Another problem is that multivitamin manufacturers often use the cheapest possible ingredients, such as folic acid instead of natural folate – the consequences of which we discussed above.

Which supplements may be necessary?

At this point you might be thinking I’m against supplementation entirely. Not so. No matter how well we eat, some nutrients are difficult to obtain enough of from food alone. There are also circumstances where are need for certain nutrients may increase, such as vitamin C during infections and magnesium with blood sugar imbalances or metabolic problems. In these cases, it makes sense to supplement selectively with beneficial nutrients.

The five nutrients I recommend most people supplement with are:

• Vitamin A
• Vitamin D
• Vitamin K2
• Magnesium
• Vitamin C

Vitamin A (Retinol)

Vitamin A is important catalyst for a variety of biochemical processes in the body. It’s required for assimilation of protein, minerals and water-soluble vitamins, and it also acts as antioxidant > protecting body against free-radical damage and diseases like cancer. Vitamin A plays a crucial role in reproduction, promoting full-term pregnancy and proper development of face (eyes, nose, dental arches & lips).

The RDA for vitamin A (2,600 IU) is woefully inadequate, and even then, over 25% of American consume less than half of the recommended amount. Native populations such as the traditional Inuit – which were free of modern, degenerative disease – got much more vitamin A than the average American. The Greenland Inuit of 1953, prior to much contact with the Western world, got about 35,000 IU of vitamin A per day.

Vitamin A (retinol) is only found in significant amounts in organ meats, which explains why many Americans don’t get enough of it. If you follow my recommendations in #2: Nourish Your Body, and you do eat organ meats (especially liver), you’re probably getting enough vitamin A and thus don’t need to supplement. However, if you’re like most Americans and you’ve never eaten liver in your life, you would benefit from supplementing with A.

There’s been a lot of discussion in the media about the toxicity of vitamin A. Some researchers and doctors now recommend avoiding cod liver oil because of this concern. Even Dr. Mercola has jumped on the “vitamin A is toxic” bandwagon. But is this true?

It is true that vitamin A is potentially toxic. Some evidence suggests that excess vitamin A increases the risk of osteoporosis. For example, this study showed both low and high serum A carried double risk of fractures as did optimal levels.

But if we dig deeper we find that excess vitamin A only causes problems against a backdrop of vitamin D deficiency. In his excellent article Vitamin A on Trial: Does Vitamin A Cause Osteoporosis, researcher Chris Masterjohn summarizes evidence demonstrating that vitamin D decreases the toxicity of and increases the dietary requirement for vitamin A. Studies show that supplementing with vitamin D radically increases the toxicity threshold of vitamin A. In a hypothetical 160 lb. person, vitamin D supplementation increases the toxicity threshold of vitamin A to more than 200,000 IU/d. You’d have to eat 22 ounces of beef liver or take 5 TBS of high vitamin CLO each day to get this amount. Not likely!

To meet vitamin A needs (assuming you’re not up for eating organ meats), I recommend taking high vitamin cod liver oil (CLO) to provide a dose of 10-15,000 IU per day. Cod liver oil is really more of a food than a supplement, but since it’s not a normal part of people’s diet we’ll consider it as a supplement. CLO is an ideal vitamin A source because it also contains vitamin D, which as we just learned, protects against the toxicity of A.

Vitamin D

Much has been written about the need for and benefits of vitamin D supplementation over the past several years – and with good reason. It’s absolutely critical for health, and up to 50% of Americans are deficient.

We can get vitamin D from two sources: food, and sunshine. Seafood is the only significant source of vitamin D, but you’d still have to eat a lot of it to get enough. 8-9 ounces of herring provides about 2,000 IU of vitamin D, which is a minimum daily requirement for most people to maintain adequate blood levels.

Sunlight converts a precursor called 7-dehydro-cholesterol in our skin to vitamin D3. This D3, along with the D3 we get from food, gets converted by the liver into 25-hyrdroxy-vitamin D (25D), which is what typically gets measured when you have a vitamin D test. The optimal 25D level is somewhere between 35 and 50 ng/mL.

Contrary to what some researchers and doctors have recommended, there’s no evidence that raising blood levels of 25D above 50 ng/mL is beneficial, and there’s some evidence that it may cause harm. Studies show that bone mineral density peaks at 45 ng/mL and then falls again as 25D levels rise above 45. Other studies have shown that the risk of kidney stones and CVD increase with high 25D levels, due to elevated serum calcium levels that accompany excess vitamin D.

However, we also know that vitamin A and vitamin K2 protect against vitamin D toxicity, and vice versa. As I explained in the vitamin A section, fat soluble vitamins exist in a synergistic relationship. It’s possible that the people in the studies above that experienced problems with excess 25D levels were deficient in vitamin A or K2, or both. This is why it’s so important to supplement with all of the fat-soluble vitamins together.

What about sunlight? Well, in summer mid-day sun with pale skin, 30 minutes of direct sunlight will produce 10-20,000 IU of vitamin D. But this is a best case scenario. With darker skin, or different times of year, or buildings that block the sunlight, or increased time spent indoors, we won’t be producing that much. It’s also true that aging, overweight and inflammation reduce our conversion of sunlight to vitamin D. This is why sunlight alone isn’t normally a sufficient source of vitamin D.

With this in mind, most people should supplement with D. The amount needed to maintain blood levels of 35-50 ng/mL varies depending on some of the factors I’ve listed above, but in my clinical experience it’s usually somewhere between 2,000 – 5,000 IU. With vitamin D, it’s important to test your levels, begin supplementation, and then re-test a few months later to determine the correct maintenance dose.

As with vitamin A, the best source of vitamin D is high-vitamin cod liver oil. It contains not only vitamins A & D, but also natural vitamin E and other quinones.

Vitamin K2

Vitamin K2 may be the most important vitamin most people have never heard of. It’s needed to activate proteins and it also regulates calcium metabolism (keeping it in the bones and teeth where it belongs, and out of the soft tissue where it doesn’t belong). Elevated blood calcium significantly increases the risk of cardiovascular disease (CVD), which explains why vitamin K2 has been shown to prevent atherosclerosis and heart attacks. It also strengthens bones.

Unfortunately, many (if not most) of Americans are deficient in vitamin K2. It’s important to point out that vitamin K2 is not the same as vitamin K1, which is found in green, leafy vegetables like kale and collards. Some K1 is converted into K2 in our bodies, but that conversion is inefficient in humans. It is efficient, however, in ruminant animals – which is why grass-fed dairy is the most convenient source of vitamin K2 in the diet. This is only true in animals raised on pasture, because it is eating the K1-rich grass that allows them to convert it into K2.

Most people should aim for at least 100 mcg/d from a combination of food and supplements. If you eat a large amount of cheese from grass-fed cows and pastured egg yolks, you may be able to get this amount from food alone. 100 g of hard cheese contains 67 mcg, and 6 pastured egg yolks contain about 32 mcg. Otherwise, supplementation is probably beneficial. I recommend a dosage of 1 mg/d in the MK-4 form, which is the form of vitamin K2 found in pastured dairy and the one shown to have the most benefit in clinical studies. There is another form, MK-7, that is found in fermented foods like natto, but it has not demonstrated the same properties as MK-4 in clinical studies.

Magnesium

There are few compounds in the body more important to overall health than magnesium. Over 300 enzymes need it, including every enzyme associated with ATP, and enzymes required to synthesize DNA, RNA and proteins. Magnesium also plays an important role in bone and cell membranes, as it helps to transport ions across the membrane surface.

Studies show that most Americans are deficient in magnesium. The median intake across all racial groups is far below the RDA, which is 420 mg/d for men and 320-400 mg/d for women. Although half of Americans take a multivitamin daily, most don’t contain enough magnesium to prevent deficiency.

Magnesium is also difficult to obtain from food. Nuts and seeds are the highest source, but it’s difficult to eat enough of them to meet magnesium needs without getting too much polyunsaturated fat. Another issue is that magnesium levels in food have dropped as modern soils have become increasingly depleted. What this means is that if you’re not supplementing with magnesium, you’re probably not getting enough.

And magnesium deficiency is no small thing. It has serious – even fatal – consequences. It produces symptoms like muscle cramps, heart arrhythmias, tremor, headaches & acid reflux, and it’s associated with CVD, hypertension, metabolic syndrome, diabetes, migraines, PMS, asthma, hypothyroidism. In fact, it’s hard to find a modern disease magnesium deficiency isn’t associated with.

Because of this, I think everyone should supplement with magnesium. Intake of 400 – 800 mg/d from a combination of food and supplements is an optimal range to shoot for. Since most people get less than 250 mg/d from food, a dose of 400 – 600 mg/d in supplement form is ideal. I recommend using chelated forms of magnesium like glycinate and malate, because they’re better absorbed and tend to have fewer side effects.

Vitamin C

Vitamin C is needed for building the structural components of the body, and for maintaining levels of glutathione, the master antioxidant in the body. But vitamin C deficiency is also common: studies suggest that 34% of men and 27% of women don’t get enough. This is especially true for the elderly and those struggling with chronic illness.

400 mg/d is the saturation range in healthy people, and that number is probably higher in the elderly and the sick. As with the other micronutrients in this article, it’s difficult to obtain adequate levels of vitamin C from the diet. Acerola cherries are the highest food source, with 1677 mg per 100g. A cup of cooked red peppers has 235 mg, which is one of the highest dietary sources.

I’m somewhat less certain about the need to supplement with vitamin C, but in general I recommend approximately 500 mg to 1 g of vitamin C each day. If you’re dealing with a chronic health challenge, or fighting an infection, you can take several grams a day with no toxic effects. It’s best to space the doses out to avoid diarrhea, however.

Other contenders

In addition to the fat-soluble vitamins A, D & K2, and magnesium and vitamin C, some may want to consider supplementing with selenium and iodine. Selenium plays important role in thyroid function, which affects every aspect of physiology. The recommended dose is approximately 200 mcg/d.

Selenium is plentiful in organ meats, ocean fish, and in brazil nuts. One brazil nut contains 100 mcg of selenium, but it also contains a whopping 1 g of omega-6 linoleic acid, which as you know from previous articles in the series, we want to limit significantly. This is why I don’t recommend brazil nuts as a source of selenium. Ocean fish are also good sources of selenium. 100 g of cod contains about 150 mcg.

Iodine also plays a crucial role in thyroid function, and it prevents brain damage and strengthens the immune system. The amount iodine needed for thyroid function is incredibly small: we need about a teaspoon of iodine over a lifetime to avoid deficiency. I’m not convinced humans need to supplement with iodine above what can be obtained from seafood, but some research does suggest that increased intake of iodine is beneficial. This is especially true if you’re fighting a chronic infection or dealing with a hypothyroidism caused by iodine deficiency.

But be careful: iodine can trigger and flare autoimmune diseases, especially Hashimoto’s and Graves’(autoimmune thyroid disease). In the U.S., 9 out of 10 women with hypothyroidism actually have Hashimoto’s, so the typical advice to supplement with iodine if you are hypothyroid is dangerous. I’ve written extensively about this in my special report on thyroid disease.

For those without autoimmune disease, a dose of 12.5 mg – 50 mg per day may be beneficial, but it’s best to work up slowly over time, beginning at a much lower dose.

Note: This will be my last post until the end of August. My wife and I are going up to the Sierras to hike and soak in the hot springs for a few days before the big acupuncture licensing exam next Tuesday. The day after that we head to southern Mexico to surf and relax on the beach for a couple of weeks.

I won’t have time to respond to comments while I’m away, but please do leave them and I’ll answer when I come back. I’ve got a few more articles in the thyroid series, and next up after that will be type 2 diabetes & metabolic syndrome. Have a great August!

Vitamin D is all the rage. It seems like every day another article is published in medical journals or the mainstream press about the dangers of vitamin D deficiency, and the benefits of supplementation. In this article we’re going to discuss the impacts of vitamin D on thyroid physiology and wade into the increasingly murky topic of vitamin D supplementation – specifically as it relates to thyroid disorders.

Vitamin D deficiency has been associated with numerous autoimmune diseases in the scientific literature. Vitamin D plays an important role in balancing the Th1 (cell-mediated) and Th2 (humoral) arms of the immune system. It does this by influencing T-regulatory (Th3) cells, which govern the expression and differentiation of Th1 and Th2 cells.

Vitamin D deficiency is also specifically associated with autoimmune thyroid disease (AITD), and has been shown to benefit autoimmune-mediated thyroid dysfunction.

Vitamin D has another little-known role. It regulates insulin secretion and sensitivity and balances blood sugar. This recent paper showed that vitamin D deficiency is associated with insulin resistance. And as we saw in a previous article, insulin resistance and dysglyemcia adversely affect thyroid physiology in several ways.

“Okay, big deal,” you say. “I’ll just take vitamin D supplements or get more sun.”

Not so fast. Research over the past two decades has identified a variety of mechanisms that reduce the absorption, production and biologic activity of vitamin D in the body.

• Since vitamin D is absorbed in the small intestine, a leaky and inflamed GI tract – which is extremely common in people with low thyroid function – reduces the absorption of vitamin D.
• High cortisol levels (caused by stress or medications like steroids) are associated with lower vitamin D levels. They synthesis of active vitamin D from sunlight depends on cholesterol. Stress hormones are also made from cholesterol. When the body is in an active stress response, most of the cholesterol is used to make cortisol and not enough is left over for vitamin D production.
• Obesity reduces the biologic activity of vitamin D. Obese people have lower serum levels of vitamin D because it gets taken up by fat cells.
• Not eating enough fat or not digesting fat properly reduces absorption of vitamin D. Vitamin D is a fat-soluble vitamin, which means it requires fat to be absorbed. People on low-fat diets, and people with conditions that impair fat absorption (like IBS, IBD, gall bladder or liver disease) are more likely to have low levels of vitamin D.
• A variety of drugs reduce absorption or biologic activity of vitamin D. Unfortunately, these include drugs that are among the most popular and frequently prescribed – including antacids, replacement hormones, corticosteroids, anticoagulants and blood thinners.
• Aging reduces the conversion of sunlight to vitamin D becomes.
• Inflammation of any type reduces the utilization of vitamin D.

“Okay, fine,” you say. “I’ll just get my vitamin D measured, and if it’s low, I’ll take supplements.”

If only it were that simple. We now know that certain people with normal serum levels of vitamin D still suffer from deficiency symptoms. How is this possible?

In order for circulating vitamin D to perform its functions, it must first activate the vitamin D receptor (VDR). The problem is that many people with autoimmune disease have a genetic polymorphism that affects the expression and activation of the VDR and thus reduces the biologic activity of vitamin D. Studies have shown that a significant number of patients with autoimmune Hashimoto’s disease have VDR polymorphisms.

In plain English, here’s what this means: if you have low thyroid function, you might be experiencing vitamin D deficiency even if your blood levels of vitamin D are normal. It also means that, if you have a VDR polymorphism, it’s likely you’ll need to have higher than normal blood levels of vitamin D to avoid the effects of vitamin D deficiency.

“Okay, I get it,” you say. “I may need higher vitamin D levels than the average person if I have one of those genetic defects. So tell me what my levels should be!”

Well, this is where we venture into murky territory. The question of how high vitamin D levels should be is very difficult to answer in the case of someone with autoimmune thyroid disease. Studies suggest the optimal 25(OH)D level is 35 ng/mL for the average person. Some researchers (notably Dr. John Cannell and colleagues at the Vitamin D Council) have suggested that 50 ng/mL should be the minimum level.

The bulk of the evidence, however, doesn’t support that claim. For starters, the other authors of the study Dr. Cannell used as the basis for his 50 ng/mL recommendation came to a very different conclusion from the same data. In the paper they published in the American Journal of Clinical Nutrition, they wrote that their data confirmed the previously acknowledged optimal level of 35 ng/mL – not the 50 ng/mL suggested by Dr. Cannell.

What’s more, some recent studies have shown that higher isn’t better when it comes to vitamin D. A study in the American Journal of Medicine found that, in most people, maximum bone density occurs at 25(OH)D levels between 32-40 ng/mL. When levels are pushed above 45 ng/mL, as recommended by Dr. Cannell, bone density starts to decrease. Another study published in the European Journal of Epidemiology found that South Indians 25(OH)D levels above 89 ng/mL were three times more likely to have suffered from heart disease than those with lower levels.

If you’ve been following this blog for a while, you know that we don’t put too much faith in epidemiological studies. They don’t prove causation. They only show a relationship between two variables. But the relationship of vitamin D to calcium levels also provides a plausible mechanism by which high 25(OH)D levels could increase the risk of heart disease.

Complicating the matter further, recent work by researcher Chris Masterjohn suggests that the harmful effects of vitamin D toxicity are at least in part caused by a corresponding deficiency in vitamins A & K2. The fat-soluble vitamins A, D & K2 work synergistically, as Masterjohn has described in his Cod Liver Oil Debate article and a recently published scientific paper.

Masterjohn’s hypothesis, which has been confirmed by others, raises the possibility that the higher levels of 25(OH)D that were linked with lower bone density and heart disease may be safe if vitamin A & K2 levels are sufficient. Unfortunately, there is no clinical evidence (that I’m aware of) that helps us to answer this question.

“Okay, okay,” you say. “Just tell me how much to take already!”

I wish it were easier to answer this question. Really, I do. I think about it a lot for my own patients. The research is clear that 35 ng/mL is the minimum level for optimum function for healthy people. But people with autoimmune thyroid conditions aren’t healthy. They often have GI disorders, inflammation, stress, excess weight, VDR polymorphisms and other factors that impair their production, absorption and utilization of vitamin D. This suggests that the minimum 25(OH)D level for those with AITD may be significantly higher than for healthy people.

My current approach with these patients is to do a cautious trial of raising their serum levels to a range of 60-70 ng/mL. If their symptoms improve at this level, I will then switch them to a maintenance dose while watching for clinical signs of vitamin D toxicity. These include kidney stones (also a sign of vitamin K2 deficiency), low appetite, nausea, vomiting, thirst, excessive urination, weakness and nervousness. I will also monitor serum calcium levels, because elevated calcium in the blood is a sign of vitamin D toxicity and a significant risk factor for cardiovascular disease (especially in the presence of vitamin K2 deficiency). Calcium levels above 11-12 mg/dL (or 2.8-3 mmol/L) are indicative of vitamin D toxicity.

I will also make sure these patients are getting adequate amounts of vitamin K2 and vitamin A in their diets. Sources of vitamin A include organ meats, cod liver oil and full-fat milk and cream from grass-fed cows. Sources of vitamin K2 include fermented foods like natto, hard cheeses and kefir as well as egg yolks and butter from grass-fed cows. I may also use a vitamin K2 supplement (MK-4/MK-7 combo) if patients can’t tolerate fermented foods.

Finally, if you’re interested in finding out if you have a VDR polymorphism that could be affecting your metabolism of vitamin D, Genova Diagnostics has an Osteogenomics panel that tests for them. I’m not sure how much value this test has clinically, however, since it doesn’t provide any information about how the VDR polymorphism affects vitamin D metabolism in each specific case. That’s still something that would have to be figured out using the “trial and error” process I described above.

In time we can hope that the explosion of research being conducted on vitamin D will lead to more clarity on the question of appropriate serum 25(OH)D levels for people with autoimmune diseases. For now, we have to make our best guess based on clinical results and anecdotal reports.

Exposure to sunlight prevents melanoma.

Yes, you did read that correctly.

Two independent studies published in the Feb. 2005 issue of the prestigious Journal of the National Cancer Institute (JNCI) squarely contradict the popular myth that UV light causes melanoma.

The first study evaluated the hypothesis that UV radiation increases your risk of developing lymphoma – a hypothesis that had become widely accepted in the 1990s and early 2000s. After studying nearly 7,000 subjects, the authors concluded that the opposite is actually true: increased sun exposure reduces the risk of non-Hodgkin’s lymphoma (NHL) by up to 40%. What’s more, the reduction in risk was dose-related, which means that the more sun exposure someone got, the lower their risk of cancer was.

The second study looked at the link between sun exposure and the chances of surviving melanoma, which is the deadliest form of skin cancer. Guess what? The researchers concluded that increased sun exposure decreases the chance of dying from skin cancer by approximately 50%.

At this point you might be scratching your head and wondering how this could possibly be true, in light of what we’ve been told all these years about the relationship between sunlight and skin cancer. Let’s take a closer look at what explains this phenomenon, and why you likely haven’t heard about it on the news.

Clarification

An editorial published in the same issue of JNCI begins with this statement:

“Solar radiation is a well-established skin carcinogen, responsible for more cancers worldwide than any other single agent.”

This is true. But what the authors neglect to mention is that the type of cancer they are referring to is not melanoma but other types of cancer. Melanoma is the most serious form of skin cancer because it is malignant and can metastasize (spread) to other areas of the body, often leading to death.

But 90 percent of skin cancers are not melanomas. Rather, the most common forms are basal and squamous cell carcinomas, which are often benign and easily cured by simple outpatient surgery. These non-malignant forms of skin cancer are indeed caused by solar radiation (at least according to current research). Melanomas, however, are most likely caused by lack of sunlight or excess exposure to artificial light!

The editorial mentioned two other very important facts that you aren’t likely to hear about from mainstream media sources: that melanoma is normally found in areas of the body that are not typically exposed to sunlight at all (use your imagination), and that vitamin D may be important in preventing melanoma.

Here’s what they actually had to say:

Umm, like, we already knew that.

The role of Vitamin D

It has been known for several years that sun exposure might have a beneficial effect on certain cancers. A 1999 publication of the National Institute of Health (NIH) entitled Atlas of Cancer Mortality in the United States revealed that among caucasians in the United States, cancer mortality for several prominent cancers, including cancer of the breast, prostate and colon, shows a striking latitudinal gradient. Specifically, people living in northern states have much higher rates of these cancers than those residing in the southern states.

The reason for this? Northern states get a whole lot less sunshine than southern states.

As early as 1990 it was proposed that vitamin D, which is synthesized in the skin upon exposure to UV light, might be the agent that accounts for these geographical patterns. (Garland et al. 1990) Less exposure to sunshine means less production of vitamin D. It is known that calcitriol, the active form of vitamin D3, has multiple cellular affects that could confer protection against cancer. The ability to convert the precursor to vitamin D to the active form of D3 (calcitriol) is greatly reduced at northern latitudes, and populations living far from the equator are at increased risk of vitamin D deficiency during the winter months. (Tangpricha et al. 2002)

Even more significant may be the observation that patients with malignant melanoma exhibit low levels of vitamin D3 in their blood, and that others have a problem with the receptor for vitamin D. (Hutchinson et al. 2000; Green et al. 1983) The incidence of melanoma of the skin on sites of the body intermittently exposed to sunlight is reduced among outdoor workers compared with indoor workers. (Elwood et al. 1985)

All of this points to a protective role for vitamin D against cancer in general, and melanoma in particular. But the final nail in the coffin of the “sunlight causes melanoma” hypothesis is this:

A comprehensive review of research studies from 1966 through 2003 failed to show any association between melanoma and sunscreen use! (Dennis et al. 2003)

Say what? Sunscreen doesn’t prevent skin cancer, that’s what.

Does sunscreen contribute to skin cancer?

One thing sunlight does cause is an injury to the inner layer of the skin (called the “dermis”), which leads to a wrinkling of the outer layer (called the “epidermis”). This phenomenon, which happens naturally with age but is accelerated by sun exposure, is called “solar elastosis”, or SE.

Sounds like a bad thing, right? But when researchers at the University of New Mexico studied melanoma, they found a marked decrease in the disease in patients with SE. (Berwick et al. 2005). To put it simply: more sun exposure equals lower risk of melanoma. For patients who already had melanoma, the subsequent death rate from the disease was approximately one-half as high in the group of patients with signs of SE.

I’ll give you a minute to finish cursing the “medical authorities” that have been admonishing us to slather ourselves and our children with sunscreen for decades in order to “prevent skin cancer”. As it turns out, if we followed this advice (and why wouldn’t we have? It sounded logical…) we have actually increased our chances and our children’s chances of developing not just skin cancer, but other cancers as well.

I’m sorry to scare you like that, but I feel I must in order to make this point as clearly as I can:

As we have already discussed, sunlight is a major source of vitamin D. Insufficient levels of vitamin D can result in osteoporosis, autoimmune diseases and rheumatoid arthritis – among other equally unpleasant and life-threatening conditions. When you put on those high-SPF sunscreens, not only are you increasing your risk for melanoma, you are increasing your risk of developing all of the conditions that can arise from vitamin D deficiency because you are blocking your body’s ability to synthesize vitamin D.

And while it is possible to obtain vitamin D from food, it is only present in large amounts in certain kinds of seafood – which many people do not consume regularly. The highest sources for vitamin D in food are anglerfish liver, cow’s blood (I’m not joking) and high-vitamin cod liver oil (HVCLO). It is also present in more modest amounts in chum salmon, Pacific marlin, herring, bluefin tuna, duck eggs, trout, eel, mackerel and salmon.

I’m going to go out on a limb and guess that most Americans aren’t eating these foods on a regular basis. The lack of adequate intake of vitamin D in the diet, combined with habitual use of high-SPF sunscreen and/or lack of exposure to the sun is a perfect recipe for increasing the risk of cancer for children and adults alike.

But you will not hear the sunscreen manufacturers telling you to stop using their product, and you probably won’t hear it from dermatologists in the field who have a reputation (and a history of telling people to wear sunscreen) to protect. They’ll tell you that sunburn is an important factor in melanoma formation since that’s really all they have left in terms of support for selling sunscreen. What they neglect to mention is that 1) millions of people get sunburned every year but very few develop melanoma, and more importantly, 2) if melanoma does appear, it’s most likely to appear in areas not exposed to the sun.

Nevertheless, it’s still probably a good idea to avoid getting sunburned – especially on a regular basis. But it is not a good idea to wear sunscreen, nor is it a good idea to avoid sun exposure.

The idea that sunlight causes cancer and sunscreen prevents it is another mainstream myth that has no support in the scientific literature. Just like the idea that cholesterol causes heart disease, eating fat makes you fat, and fluoride is good for your teeth. (If you still believe any of those statements, check my archives and sign up for my free email digest!)

Before closing, I must mention (briefly) the issue of vitamin D toxicity. Vitamin D is widely considered to be the most toxic of all vitamins, and dire warnings are often issued to avoid excess sun exposure and vitamin D in the diet on that basis. The discussion of vitamin D toxicity has failed to take into account the interaction between vitamins A, D and K. Several lines of evidence suggest that vitamin D toxicity actually results from a relative deficiency of vitamins A and K.
So, the solution is not to avoid sun exposure or sources of vitamin D in the diet. Rather, it ensure adequate vitamin D intake (through sunlight and food) and to increase the intake (through diet and/or supplements) of vitamins A & K. Stay tuned for a future post on the interaction between vitamins A, D & K and their relevance to human health.

In the meantime, this is what I recommend for protecting against cancer and both deficiency and toxicity of vitamin D:

As always, leave a comment or contact me with questions!