Are You Getting Enough Vitamin D and Getting It in the Right Form?

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Are you getting enough vitamin D and are you getting it in the best form to maximize its benefits?

Vitamin D plays a number of key roles in human health. Although it’s called a vitamin, vitamin D behaves more like a hormone by affecting proteins that control bone build-up and breakdown and immune cells that regulate your immune system.

Vitamin D is an immune modulator, meaning it boosts the immune system’s ability to fight off foreign invaders like viruses but also helps calm an overactive immune system that leads to inflammation.

Low Vitamin D and Disease Risk

Why should we be concerned about vitamin D? Low vitamin D levels have been linked with a number of health problems including autoimmune diseases, osteoporosis, muscle fatigue and pain, depression, heart disease, obesity, and, possibly, some types of cancer.

However, research is still preliminary and only shows an association between vitamin D and such conditions. It doesn’t necessarily mean that low vitamin D causes these problems or that taking a supplement prevents them. There could be some other factors common to people low in vitamin D.

It’s not clear yet whether low vitamin D increases the risk of any disease, as the results of studies are inconsistent, and we can’t say for sure whether taking a vitamin D supplement prevents certain health problems, but it’s clear that you need a certain amount of vitamin D in your system for good health. You don’t want to be deficient!

Can You Get Enough Sunlight to Maintain a Healthy Vitamin D Level?

Unfortunately, a significant number of people have low or borderline-low levels of vitamin D, particularly older people and folks who live in Northern latitudes and those who aren’t exposed to daily sunlight. Why do so many people have a sub-optimal vitamin D level? One factor is sunlight or the lack of sun exposure.

When sunlight hits your skin, it converts vitamin D precursors on your skin to a form that can be further activated by your liver and kidneys. That’s why experts recommend exposing your skin to the sun for 10 to 15 minutes several days each week.

Unfortunately, this amount of sunlight exposure may not be enough to optimize vitamin D for people who live in Northern latitudes where the sun’s rays are weak during the winter. That’s why sun exposure is not always a reliable way to meet your body’s vitamin D requirements.

In addition, people who with darker skin have more melanin and melanin absorbs some of the UVB rays from the sun, the ones you need to make vitamin D. Therefore, if you have more melanin in your skin, you need greater sun exposure to make the same amount of vitamin D as someone with light skin.

Obese people and people over the age of 60 also need more sun exposure to maintain a healthy vitamin D level. So, there isn’t a “one size fits all” prescription for vitamin D exposure.

Vitamin D from Sunlight versus Vitamin D Supplements

It’s usually better to get vitamins and nutrients naturally through diet, but that isn’t always possible with vitamin D. Most foods contain only modest quantities of the “sunshine vitamin.” Salmon, sardines, cod, liver oil, and egg yolk are among the best dietary sources of vitamin D. Plus, some breakfast cereals, orange juice, yogurt, and milk is fortified with vitamin D but, as you’ll soon see, these sources aren’t equal in terms of vitamin D activity.

The problem with vitamin D in fortified foods like milk and breakfast cereals is it isn’t always in its“optimal” form. There are two types of vitamin D. Vitamin D3, also called cholecalciferol, is the form your body makes when you expose your skin to sunlight. Fatty fish, like salmon, and cod liver oil contain this type of vitamin D too. The other form is ergocalciferol or vitamin D2. This type is made by exposing fungi to ultraviolet light.

Why is this important? Research shows that vitamin D3 has more vitamin D activity than vitamin D2 from non-animal sources. In one study, researchers gave 335 women either vitamin D3 from animal origin or orange juice fortified with vitamin D2. Vitamin D3 was twice as effective at boosting the vitamin D blood levels of subjects in the study.

If you’re using sunlight to keep your vitamin D up, you’re getting the most biologically active form since sunlight triggers a sequence of events that tells your body to produce vitamin D3. But if you’re eating foods fortified with vitamin D, like cereal, orange juice, or milk, you may be getting vitamin D2, the less active form. If you’re eating whole foods sources of vitamin D, like wild-caught salmon, you get vitamin D3, the more potent type. The same is true of sun exposure.

What about Vitamin D Supplements?

Some people turn to vitamin D supplements (affiliate). Supplements are a good option for people who are deficient and don’t get enough vitamin D naturally but make sure you know what your blood level of vitamin D is before supplementing. Knowing your number ensures you’re taking enough to raise your vitamin D but not getting enough to be toxic. Your doctor can do a blood test to check your vitamin D level.

If you’re deficient, read the label and choose a supplement with the vitamin D3 or cholecalciferol form, not vitamin D2 or ergocalciferol, to ensure you’re getting maximal benefits. Make sure your doctor knows you’re taking a vitamin D supplement since very high levels can be toxic, and get your blood levels checked every six months while you’re on a vitamin D supplement.


I’m a family physician who believes in the power of lifestyle to transform health and prevent disease. Food is the best medicine!

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