“Vitamin D should have never been called a vitamin.” That’s the phrase with which the national nutrition expert opened her lecture regarding the power of the hormone we commonly refer to as vitamin D. Are you getting enough of this important essential nutrient? At this time of the year, cooped up and relying on electricity and gas to keep us warm, we are certainly separated from one natural source of vitamin D; the sun.
If you’re a history buff you may already know that vitamin D deficiency was a significant disease in the early 1900s. Crooked bone growth, especially of the legs was so prevalent at that time that many people considered it unavoidable. Vitamin D has been mandated by the government to be added to processed cow’s milk since the 1930s. Just like iodine in commercial salt, cow’s milk was chosen as a food item that many people consumed so that more Americans could receive adequate vitamin D. With the addition of Vitamin D to cow’s milk rickets, also known as osteopenia, was reduced to a rare occurrence.
Vitamin D receptors are found in nearly every cell in the body. Researchers over the past decade have pointed towards low levels of Vitamin D as a possible factor in autoimmune diseases such as multiple sclerosis and type 1 diabetes, cancer, osteopenia and osteoporosis, depression, mood disorders, ADHD, and many other conditions. Vitamin D plays a significant role in helping bone layers stay strong and reducing inflammation throughout the body. As vitamin D is used up and not replaced, bones can begin to ache deeply. As a registered dietitian who commonly reviews the lab work of my clients, I can tell you that vitamin D deficiency is more common than you think.
With the help of sun exposure, along with a little kidney and liver input, humans can manufacture their own active form of vitamin D from the inactive form in our skin. But here comes the big IF.
IF you live anywhere north of Atlanta (like York, PA) you cannot make enough vitamin D from sunlight basically from November through February. And even after March vitamin D is only produced during peak sunlight hours of the day. UVB radiation does not penetrate glass, so exposure to sunshine indoors through a window does not produce vitamin D. Due to concerns regarding cancer risk related to sun exposure, some experts recommend supplementation rather than sun exposure as in the case of breastfed babies. If you have been low in vitamin D in the past, took a supplement prescribed by your doctor, and are not taking the supplement now, there’s a significant chance you’re low again if you haven’t ramped up your dietary sources.
Cow’s milk is commonly fortified with vitamin D. There is a misconception though that all dairy products are good sources of vitamin D. While all cow’s milk products are good sources of calcium, many yogurts and cheeses are made with unfortified milk, lacking the vitamin D supplementation. Checking out the back of your yogurt is an easy way to tell. First check the serving size, especially if the yogurt is in a large container. Currently, manufacturers are not required to list the percent vitamin D of the food unless it’s fortified, but the new food label that’s being planned will require vitamin D to be listed. The percent listed shows how much of 400 IU you’re getting in that food product.
If you’ve chosen to avoid cow’s milk your body still needs a sufficient source of vitamin D. Unfortunately there are not many good sources of vitamin D in foods which makes the deficiency all the more likely. The amount that is recommended for adults varies based on authorities, but licensed physicians and registered dietitians often recommend 800 to 1000 IU per day.
Fatty fish like salmon, tuna, and mackerel can contain from 300 to 400 IU per 4 ounce serving and consuming the actual soft bones of a fish like sardines can contribute even more. Two sardines contains 46 IU, about the same as one egg yolk.
Mushrooms are also a source of Vitamin D2, though a poorer quality vitamin D than Vitamin D3, the type found in animal fats and can vary in vitamin D content. One serving (8 ounces) of fortified cow’s milk or dairy alternative typically contains 100 IU and fortified cereal grains 40 to 100 IU per serving. A single tablespoon cod liver oil contains 1360 IU, but some experts frown upon the excessive vitamin A content of cod liver which can lead to a toxic level.
If none of those foods commonly show up in your market basket and you’re hiding indoors you may just want to look at pumping up your dietary sources of this vital nutrient until the sun warms us again in spring.