Celiac.com 04/26/2007 - My fingernails were shredding and I was a bit out of it mentally, missing obvious things. I’ve had to stop eating many foods because I have intolerances to almost everything I used to eat before I went gluten-free, and I wondered if I had dropped some essential nutrients when I cleared all of those foods out of my diet. So I checked my diet for nutrient deficiencies, using the USDA nutrients database at www.nal.usda.gov/fnic/foodcomp/search. I’m sure there’s software that works with this database but I wrote a little computer program to analyze my diet. I have an electronic food scale, so weighing food is easy.
The most important thing I found is that I’m low on vitamin D. You can get vitamin D from food, or from a supplement, and from the ultraviolet B in sunlight; many of us, like me, may get almost none from any of those sources. And—this is important for a lot of us—vitamin D deficiency can cause a lot of symptoms including immune system problems! I went looking on Medline and it was mentioned as having anti-inflammatory properties, as preventing cancers such as colon cancer and lymphoma; preventing infections, and helping with autoimmune diseases. Gluten intolerance is less common in the middle east and more common in northern Europe. I’ve seen this explained as the result of evolution, since wheat has been used for longer in the Middle East. But I wonder if people in the north are also more likely to be gluten intolerant (an autoimmune disease) because they don’t get as much vitamin D. It may also explain why people get more colds during the winter season when there’s less sunlight. Vitamin D deficiency is best known for causing rickets in children and osteomalacia (softened bones, muscle weakness and pain, tender sternum) in adults. Osteomalacia is often misdiagnosed as fibromyalgia, because the symptoms are similar. Rickets is increasing in the U.S., especially among black children. Most post-menopausal bone loss in women occurs during the winter. It can take months of increased vitamin D intake to correct the health problems caused by deficiency.
There are only a few significant dietary sources of vitamin D. In the U.S., almost all milk is fortified with vitamin D to 100 IU per cup, so you should get the recommended daily intake of 400 IU if you drink 4 cups of milk per day. However, milk often doesn’t have as much vitamin D as is claimed on the label. Some cereals, like Kellogg’s Cornflakes, have small amounts of added vitamin D. Typically, 10 cups of fortified cereal would give you the RDI. The government encourages fortification of milk and cereal so that fewer children will develop rickets. Otherwise—you would get the RDI from nine oysters, or about 4 ounces of fatty fish like salmon or tuna, or a teaspoon of cod liver oil. Many other kinds of fish have only small amounts. You’d have to eat 2 pounds of cod to get the RDI. The only natural vegan source of vitamin D is Shiitake mushrooms. Just like people, mushrooms make vitamin D when they’re exposed to ultraviolet. About 13 sun-dried shiitake mushrooms contain the RDI. And that’s it. Many of us on gluten-free diets are also not eating dairy or fortified cereals, so unless we have a passionate love-affair with fish or oysters or shiitake, we would be getting almost no vitamin D from food.
You can get vitamin D the natural way, from the sun. It takes exposure to sunlight outside (not under glass) on your hands and feet for about fifteen minutes a day. I was not sure what was meant by “direct sunlight”. I read someplace that ultraviolet is scattered over the whole sky. Unlike visible light, the whole sky shines with ultraviolet. Clouds would filter out some of it. People with dark skin require more time in the sun, so many black people develop a deficiency. Using even low-SPF sunscreen prevents your body from making vitamin D. The farther from the equator you live, the less UVB there is in the winter sunlight, because the sun is closer to the horizon in the winter and the sunlight filters through more atmosphere before it gets to you. At the latitude of Boston, and near sea level, there isn’t enough UVB radiation between November and February for one’s body to make vitamin D.
You have probably heard the public health advice to wear sunscreen—the same ultraviolet B that generates vitamin D in your body also causes skin cancer and ages skin. The small amount of exposure to sunlight required is probably only a very small cancer risk and would cause little photo-aging of the skin. Unfortunately I wasn’t able to find quantitative information about how carcinogenic fifteen minutes’ daily sun exposure would be. There are also vitamin D lights, which are probably also a healthful choice.
I have severe immune system problems. I tested positive for 53 inhalant allergies—my body had developed allergies to almost all the allergens around. I get sick for days if I eat almost any of the foods that I ate while I was eating gluten. I even get sick from a couple of foods that, so far as I can remember, I only started eating on a gluten-free diet. So I live on an exotic-foods diet. I’ve had a hellish time trying to get allergy shots. At a concentration of 1 part in 10 million they make me sick for a couple of days while the normal starting concentration for allergy shots is 1 in 100,000. I’m plagued by bladder infections. With cranberries being one of my intolerances, I can’t even use them to help prevent the infections.
I’ve certainly been short of vitamin D. I live in the north, and I’m always careful to use high-SPF sunscreen when I go outdoors. I can’t eat milk, fish, shellfish or mushrooms, so I can’t get a significant amount of vitamin D from food. I haven’t been taking any vitamin supplements, because almost all have traces of protein from some food that makes me sick. It would be lovely if vitamin D deficiency turned out to be part of the cause of my very burdensome immune problems. I’m skeptical because I was getting vitamin D from a supplement and/or from my diet up until 2 years ago, when I found I had a vast number of hidden food intolerances, and I started having reactions to vitamin pills. Fortunately there is a vitamin D supplement that I can take—vitamin D3 made by Pure Encapsulations. The ingredients in the capsule are made from wool and pine trees. I’ll find out if it helps over the next few months.
Vitamin D causes disease when taken in large amounts, so if you think you are deficient, don’t take too much to make up for it. Vitamin D is a hormone—it’s not something to take in mega-doses, any more than, hopefully, one would take a mega-dose of estrogen or testosterone. If your doctor recommends a high dose, they should do regular blood tests to keep track of your vitamin D level. It’s pretty safe to take up to 2000 IU per day on your own. Dr. Michael Holick, a vitamin D researcher at Boston University and author of The UV Advantage, believes that people need about 1000 IU per day. I asked a family doctor, who said they suggest 400-800 IU per day for middle-aged women. However, it might be a good idea for gluten intolerant people to take more, about 1000 - 2000 IU per day, since we may have difficulties absorbing vitamins and celiac disease is an autoimmune disease.
Vitamin D is very important, just as all the vitamins are. But we are conditioned by the media, and tend to think more about vitamins C and E, which get a lot of attention because they’re antioxidants. Vitamin D was the absolutely last one I looked at. Then I found that it was my most serious deficiency! And nutrient deficiencies are not a trendy topic, so the possibility of developing deficiencies is something people tend to forget while trying to improve their diets. Many people who avoid gluten also have other food intolerances, or are on some other kind of special diet, and it would be an excellent idea to go to the USDA database and find out whether their new diet is giving them enough vitamins and minerals. It certainly helped me. I feel more cheerful and alert, like my mind woke up on a sunny day.
It’s best to get as much as possible from one’s diet, too. Whole foods have a lot in them that’s good for the body that research hasn’t yet identified, and if your diet gives you the RDA of all the vitamins and minerals, it will also be giving you other healthful nutrients that will do you a lot of good. This might also be true of vitamin D. Maybe it’s better to get a small amount of ultraviolet, like an iguana sitting under a UV lamp, instead of taking pills. UVB might be healthy in ways we don’t yet know about.
Vitamin D is a bit like stored-up sunlight. You can catch it for yourself from the sun when it’s high in the sky, you can eat the sunlight the fish have gathered for you, or you can take a supplement and keep packed sunlight on your shelf.