As the increase in prevalence of food allergies has been debated over the last decade, several explanations have been suggested, but none have been proven. One idea that has some research evidence to back it up is that vitamin D may play a role. It has been noted that while the number of food allergies in the U.S. has gone up, the levels of vitamin D in the population overall has gone down. Is this just a coincidence or is there a real connection?
What Is Vitamin D?
Vitamin D is an essential micronutrient and a fat-soluble vitamin. It is needed for absorbing calcium and strengthening bones. It is also needed for good cell growth, for proper immune system function and for reducing inflammation. Vitamin D deficiency in kids is called rickets and it can have lifelong consequences for bone structure. Without enough vitamin D, a child’s developing bones become brittle, weak and deformed. In adults, a deficiency can also weaken the bones and trigger or worsen osteoporosis.
We get most of our vitamin D from the sun, which is why it is sometimes called the sunshine vitamin. When our skin absorbs ultraviolet light from the sun, it triggers the manufacturing of the vitamin. You can also get vitamin D in your diet through foods like fish, eggs and fortified foods or supplements. However, the main route for getting enough of this vitamin is through sunlight.
The Connection Between Food Allergies and Vitamin D
The realization that the decrease in vitamin D levels has coincided with the increase in food allergies has gotten a lot of attention. We know that areas of the globe that are farther from the equator, and therefore that receive less sunlight, see more cases of food allergies. Studies have also found that children born in fall or winter, when there is less sunlight, are at a greater risk for having food allergies.
It has also been shown that infants who started eating eggs earlier were less likely to have food allergies. Egg is one of the few food sources of vitamin D that infants are likely to eat. Finally, there have been direct connections showing that individuals with lower vitamin D levels in their blood are more likely to have food allergies.
Vitamin D in Pregnancy
All the connections between vitamin D and food allergies are intriguing, but they don’t really prove anything. They do not prove that a lack of vitamin D can cause, or even be a risk factor for, allergies. A very recent study, however, has found a more direct link and some interesting evidence that could prove the connection true.
Researchers studied over 1,200 women and their children from early pregnancy until the children turned seven years old. They found that those women who had greater vitamin D intake during pregnancy were associated with 20 percent less incidence of hay fever. This isn’t a food allergy, but if a connection can be made between vitamin D and any allergy, it could relate to food allergies too.
The possible explanation for why vitamin D might play a role in allergy development is its involvement in the immune system. It has been shown that the vitamin can modulate, or change, the immune system and the way it responds. There is much more to learn about it, but it could be that insufficient vitamin D has a role to play in how we develop allergic reactions.
The takeaway message from all this research is that vitamin D is as important as ever. It has long been known that deficiencies in the vitamin have serious consequences for our bones, but now there may be even more reasons to be sure we get enough of this crucial nutrient. For pregnant women it may be especially important in mitigating the risk of food and other allergies. If you are expecting, talk to your doctor about vitamin D and the possibility of using a supplement.