Dietary Supplements for Eczema (Atopic Dermatitis)

Are there dietary supplements that can help with atopic dermatitis?

Atopic dermatitis, more commonly known as eczema, ranks “as the skin disease with the greatest health burden worldwide” because it’s just so common, affecting maybe one in ten kids and about 3 percent of adults, causing patches of red, itchy skin. Topical steroids, like cortisone cream, have been “the mainstay treatment” since their Nobel Prize-winning discovery in 1950.

People are scared of steroids, though, and “it is not uncommon for patients to express irrational fear and anxiety about using topical corticosteroids”—steroid creams and ointments. This phobia may arise from confusing topical steroids with oral or injected steroids, which have different effects. Really potent topical steroids can thin your skin, but skin thickness should return to normal a month after stopping. So, yes, topical steroids can cause side effects, but the concern people have “seems out of proportion” to the small risk they actually pose. Still, if there’s a way you can resolve a problem without drugs, that’s generally preferable. What did they do for eczema before the 1950s?

In the 1930s, some researchers tried using vitamin D dissolved in corn oil, and to their surprise, it worked—but so did the corn oil without the vitamin D they were using as a control. Others reported cases improving after feeding flaxseed oil and even ingesting lard, from a study “aided by a grant from the National Live Stock and Meat Board,” which apparently did not want to be left out of the action. The problem is that none of these studies had a control group. So, yes, after feeding someone corn oil for 12 to 18 months, they got better—but maybe they would have gotten better anyway. You don’t know until you put it to the test. 

Nearly all of those researchers who claimed benefit from the use of the various fats apparently “lack[ed]…any great interest in a controlled series,” but one researcher tested some oils and found no evidence of benefit over routine treatment. Indeed, as you can see at 2:06 in my video Eczema Treatment with Evening Primrose Oil vs. Borage Oil vs. Hempseed Oil, most got better either way, which suggests that the previous “benefits claimed may be due to the usual treatment, with perhaps a dash of enthusiasm.”

By then, hydrocortisone was out, so the medical community gave up on dietary approaches—until a letter was published in 1981 about the treatment of eczema with supplements of evening primrose oil, which contains gamma linolenic acid, an anti-inflammatory omega-6. And, indeed, when it was put to the test, it seemed to help, but then a subsequent larger study found no effect. Whenever there are conflicting findings, it helps to do a meta-analysis, where you put all the studies together. So, there was the study that showed benefit, the one that didn’t, and seven other studies. What did those find? Seven out of the seven showed benefit. “The results show that the effects of Epogam [a brand of primrose oil supplement] are almost always significantly better than those of placebo.” Case closed, right? Well, the analysis was funded by the supplement company itself, which can be a red flag, and where exactly were the other seven studies published? They weren’t. The company just said it did those seven studies but never released them. When asked to hand them over, the company said it would but never did, even threatening a lawsuit against researchers who dared to question the studies’ efficacy.

An independent review failed to find evidence that evening primrose oil or borage oil worked better than placebo. “As we bid goodnight to the evening primrose oil story, perhaps we can awaken to a world where all clinical trial data…reach the light of day…” 

Borage oil actually has twice the gamma linolenic acid as evening primrose yet it still didn’t work, but that didn’t stop researchers from trying hempseed oil, which “has been used as a food and medicine for at least 3000 years in China.” Researchers tried giving about a quarter cup of hempseeds’ worth of oil to people every day for a few months and found significant improvements in skin dryness, itchiness, and the need for medications—but not compared to placebo. In fact, studies of dietary supplements across the board, whether fish oil, zinc, selenium, vitamins D, E, or B6, sea buckthorn oil, hempseed oil, or sunflower oil, overall, showed “no convincing evidence that taking supplements improved the eczema of those involved.” That’s disappointing, but wait a second. That’s just for oral supplements. What about natural remedies applied topically? I discuss that in my video Eczema Treatment with Coconut Oil vs. Mineral Oil, vs. Vaseline.

Meta-analyses can be skewed the other way, too, when negative results are quietly shelved so only positive findings are published. Antidepressant medications are a classic example of this publication bias. Check out my coverage of it in my video Do Antidepressant Drugs Really Work?.

As I queued up at the end, I cover topical natural treatments in my next video, Eczema Treatment with Coconut Oil vs. Mineral Oil vs. Vaseline.

What about skipping the lard and trying to eat more healthfully? See what happened in Treating Asthma and Eczema with Plant-Based Diets.


For more on skin health, check out:

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

2400 Units of Vitamin D a Day for Fibromyalgia

Fibromyalgia, one of the most common joint and muscle diseases, afflicting millions of Americans, is characterized by widespread musculoskeletal pain, often accompanied by other symptoms, such as fatigue. The medical profession used to think it was all in people’s heads, “but today there is irrefutable evidence” that it is indeed a disorder of the body and not just the mind.

Back in 2003, an influential paper was published out of the Mayo Clinic in which a shocking 93 percent of fibromyalgia-type patients were found to be vitamin D deficient, so the researchers concluded that all such patients are at high risk of severe vitamin D deficiency. Wait a second, said the skeptics. There was no control group, and where’s the Mayo Clinic located? Minnesota. Maybe 90 percent of everyone in Minnesota is deficient in vitamin D.

When controlled studies were done, some did indeed find that those suffering from these kinds of pain syndromes were significantly more likely to be D deficient, but other studies did not find this. Even if all the studies did have the same findings, though, that doesn’t mean that low vitamin D levels cause fibromyalgia. Maybe chronic, widespread pain disorders like fibromyalgia cause low vitamin D. After all, it’s the sunshine vitamin, and perhaps fibromyalgia patients aren’t running around outside as much as healthy controls. To know if vitamin D is contributing to the disease, you have to put it to the test. 

Various studies found that the majority of those with pain syndromes and low D levels appeared to benefit from vitamin D supplementation, and clinical improvement was evident in up to 90 percent of patients. But these studies weren’t controlled either. Maybe the subjects would have gotten better on their own without the supplements, or maybe it was the placebo effect. There are many examples in the medical literature of treatments that looked great in uncontrolled trials, like hyperbaric oxygen therapy for multiple sclerosis, but when put to the test in randomized controlled trials, they failed miserably.

And, that’s what seemed to happen in the first randomized controlled trial of vitamin D for a fibromyalgia-type syndrome in 2008. As you can see at 2:55 in my video The Best Supplement for Fibromyalgia, researchers saw no significant difference in pain scores, though the study only lasted three months, and, in that time, the treatment was only able to get the vitamin D blood levels up to about 30. Unfortunately, no controlled study had ever been done pushing levels any higher, until 2014. As you can see at 3:23 in my video, fibromyalgia patients were given up to 2400 units of vitamin D a day for 20 weeks and their D levels rose up to about 50. Then, once they stopped the vitamin D, their levels came back down to match the placebo. That was reflected in their pain scores: a significant drop in pain severity while they were on the D and then back to baseline when they came off of it. The researchers concluded “that this economical [in fact, over-the-counter] therapy with a low side effect profile may well be considered in patients with FMS [fibromyalgia syndrome].”


What changes in our diet may help combat fibromyalgia? See my videos Fibromyalgia vs. Vegetarian and Raw Vegan Diets and Fibromyalgia vs. Mostly Raw & Mostly Vegetarian Diets.

What else can vitamin D supplements do? Check out:

What’s the best way to get vitamin D? See:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Vitamin D Supplements for Increasing Aging Muscle Strength

We have known for more than 400 years that muscle weakness is a common presenting symptom of vitamin D deficiency. Bones aren’t the only organs that respond to vitamin D—muscles do, too. However, as we age, our muscles lose vitamin D receptors, perhaps helping to explain the loss in muscle strength as we age. Indeed, vitamin D status does appear to predict the decline in physical performance as we get older, with lower vitamin D levels linked to poorer performance. As I discuss in my video in my video Should Vitamin D Supplements Be Taken to Prevent Falls in the Elderly?, maybe the low vitamin D doesn’t lead to weakness. Rather, maybe the weakness leads to low vitamin D. Vitamin D is the sunshine vitamin, so being too weak to run around outside could explain the correlation with lower levels. To see if it’s cause and effect, you have to put it to the test.

As you can see at 1:01 in my video, about a dozen randomized controlled trials have tested vitamin D supplements versus sugar pills. After putting them all together, we can see that older men and women taking vitamin D get significant protection from falls, especially among those who had started out with relatively low levels. This has led the conservative U.S. Preventive Services Task Force, the official prevention guideline setting body, and the American Geriatric Society to “recommend vitamin D supplementation for persons who are at high risk of falls.”

We’re not quite sure of the mechanism, though. Randomized controlled trials have found that vitamin D boosts global muscle strength, particularly in the quads, which are important for fall prevention, though vitamin D supplements have also been shown to improve balance. So, it may also be a neurological effect or even a cognitive effect. We’ve known for about 20 years that older men and women who stop walking when a conversation starts are at particularly high risk of falling. Over a six-month timeframe, few who could walk and talk at the same time would go on to fall, but 80 percent of those who stopped walking when a conversation was initiated ended up falling, as you can see at 2:14 in my video.

Other high-risk groups who should supplement with vitamin D include those who have already fallen once, are unsteady, or are on a variety of heart, brain, and blood pressure drugs that can increase fall risk. There’s also a test called “Get-Up-and-Go,” which anyone can do at home. Time how long it takes you “to get up from an armchair, walk 10 feet, turn around, walk back, and sit down.” If it takes you longer than ten seconds, you may be at high risk.

So, how much vitamin D should you take? As you can see at 3:00 in my video, it seems we should take at least 700 to 1,000 units a day. The American Geriatric Society (AGS) recommends a total of 4,000 IU a day, though, based on the rationale that this should get about 90 percent of people up to the target vitamin D blood level of 75 nanomoles per liter. Although 1,000 IU should be enough for the majority of people, 51 percent, the AGS recommends 4,000 IU to capture 92 percent of the population. That way, you don’t have to routinely test levels, since 4,000 IU will get most people up to the target level and “is considerably below the proposed upper tolerable intake of 10,000 IU/d.” The AGS does not recommend periodic mega-doses.

Despite the AGS’s recommendation, because it’s hard to get patients to comply with pills, why not just give people one megadose, like 500,000 units, once a year, perhaps when they come in for their flu shot? That way, every year, you can at least guarantee an annual spike in vitamin D levels that lasts a few months, as you can see at 4:00 in my video. It’s unnatural but certainly convenient, for the doctor at least. The problem is that it actually increases fall risk, a 30 percent increase in falls in those first three months of the spike. Similar results were found in other mega-dose trials. It may be a matter of too much of a good thing. See, “vitamin D may improve physical performance, reduce chronic pain, and improve mood” so much that people start moving around more and, thereby, increase fall risk. When you give people a whopping dose of vitamin D, they get a burst in physical, mental, and social functioning, and it may take time for their motor control to catch up to their improved muscle function. It would be like giving someone a sports car when they’ve been used to driving a beater. You’ve got to take it slow.

It’s possible, too, that such unnaturally high doses may actually damage the muscles. The evidence the researchers cite in support is a meat industry study showing you can improve the tenderness of steaks by feeding cattle a few million units of vitamin D. The concern is that such high doses may be over-tenderizing our own muscles, as well. Higher vitamin D levels are associated with a progressive drop in fracture risk, but too much vitamin D may be harmful, as you can see at 5:29 in my video.

The bottom line is that vitamin D supplementation appears to help, but the strongest and most consistent evidence for prevention of serious falls is exercise. If you compare the two, taking vitamin D may lower your fall risk compared to placebo, but strength and balance training with or without vitamin D may be even more powerful, as you can see at 5:41 in my video.


Other studies in which vitamin D supplements have been put to the test in randomized placebo-controlled studies, effectively proving—or disproving—their efficacy, are featured in videos such as:

That brings up a number of important questions, which I answer in these videos:

Unfortunately, most supplements are useless—or worse. Here are some additional videos on supplements I’ve produced that may be of interest to you:

For more on the benefits of exercise, see Longer Life Within Walking Distance and How Much Should You Exercise?

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: