How to Avoid Vitamin D Deficiency in the Winter

How to Avoid Vitamin D Deficiency in the Winter

Vitamin D is more than a vitamin. In fact, some experts believe vitamin D would best be classified as a hormone rather than a vitamin. No wonder! Vitamin D plays a number of vital roles in the human body. You know it best for its role in boosting calcium absorption and guarding against bone loss. Yet, vitamin D also helps balance the immune system and protect against infection. At the same time, it helps guard against an “overreaction” of the immune system that could lead to inflammation or autoimmune disease. Preliminary studies also show that vitamin D may protect against other health problems, including obesity, high blood pressure, depression, and type 2 diabetes.

Are You Getting Enough Vitamin D?

The problem is most of us don’t get enough vitamin D. The rate of vitamin D deficiency is especially high in people over the age of 65. In this population, up to 70% of men and women may be deficient. How bad is the problem? Some studies show that a third of people of all ages are deficient or marginally deficient in vitamin D.

The time when we have to be most aware of getting enough vitamin D is in the winter. That’s because the best source of vitamin D is exposure to sunlight. On your skin is a vitamin D precursor called 7-dehydrocholesterol. When sunlight strikes your skin, it converts this precursor to “pre-vitamin D.” Your liver and kidneys go on to modify pre-vitamin D to a form your body can use.

All goes well, as long as you have enough of the 7-dehydrocholesterol precursor on your skin and you get enough direct sunlight to activate it. As it turns out, a lot can go wrong and cause you to end up short on vitamin D. For one, you don’t produce as much 7-dehydrocholesterol as you age. Plus, most of us spend time indoors in the winter where our skin isn’t exposed to sunlight. Typically, the months between November and March are when you get the least exposure to vitamin D. If you happen to live in a Northern area of the country, you get little direct sunlight in the winter even if you spend time outdoors.

What about diet? Unlike most vitamins that you get through food, it’s hard to get enough vitamin D from food, even if you eat a healthy diet. The only foods that naturally have respectable amounts of vitamin D are eggs and oily fish, like wild-caught salmon. Some foods are fortified with vitamin D, such as packaged cereals, milk, some milk substitutes, yogurt, and orange juice. However, if you’re vegetarian, vegan, or avoid packaged foods, you’ll likely get little vitamin D from diet.

Risk Factors for Vitamin D Deficiency:

·       Dark skin pigment

·       Being obese

·       Over the age of 70

·       Living in a Northern latitude

·       Spending time indoors

·       Age (vitamin D deficiency becomes more of a risk as you age)

·       Having a condition that reduces vitamin D absorption (inflammatory bowel disease, Celiac, etc.)

·       Having had surgery for weight loss

How Much Vitamin D Do You Need?

The recommendations are 600 I.U. of vitamin D daily and 800 I.U. if you’re over the age of 70, although some experts believe this quantity is too low. You can get this amount by exposing your skin to sunlight 10 to 15 minutes a day, without sunscreen. That works well for the spring and summer months but it’s harder in the winter. You do store some vitamin D in your liver, which helps, but, especially if you’re at high risk for vitamin D deficiency, a little outdoor time might not be enough.

How to Avoid Vitamin D Deficiency

With vitamin D playing such an important role in health, avoiding deficiency should be a top priority. What’s the best way to do that? First, ask your doctor to check a 25 hydroxyvitamin D test to see if you’re within the normal range. This is especially important if you have one or more risk factors for vitamin D deficiency. Unfortunately, this test is not used nearly as often as it should be. If the results show you’re deficient, you may need high doses for short periods of time to make up the shortfall. Once you’ve achieved a normal level, you then focus on maintaining it.

What can you do to avoid future vitamin D deficiency? Make sure you’re spending 10 to 15 minutes daily outdoors without wearing sunscreen. When you take a winter vacation, head South to a spot that gets lots of direct sunlight. Take advantage of every opportunity to maintain your vitamin D level. Include more foods that contain vitamin D in your diet. Although you have limited options, a serving of salmon has just over 450 I.U., almost a day’s worth. Add milk or milk substitute to your coffee and oatmeal. Yogurt is another vitamin D fortified option. One large egg has around 40 I.U. of vitamin D, but each little bit counts.

If you eat a vegan diet, especially if you get little direct sunlight, your risk of vitamin D deficiency is high. Most of the foods fortified with vitamin D are off limits to vegans. So, be sure to check your vitamin D level. Surprisingly, there is one plant-based food that has significant quantities of vitamin D. If you grow mushrooms in ultraviolet light, most grow in the dark, they produce vitamin D. You can make your own vitamin D mushrooms by buying mushrooms at your local grocery store and placing them in direct sunlight for several hours. Maitake, shiitake, or even the common button mushroom will work. Pretty amazing, huh?

What about Supplements?

It’s usually a good idea to get your vitamins from whole foods sources, however, it’s not always possible with vitamin D. If you can’t get at least 10 minutes of sunlight on your skin most days of the week, you may need a vitamin D supplement. Check your vitamin D level and you’ll have a clearer idea of whether a supplement is appropriate for you.

If you don’t mind spending money, around $400.00, you can buy a special vitamin D lamp, approved by the FDA. This lamp, called the Sperti, can boost your vitamin D level at home in as little as a few minutes per week. It delivers the ultraviolet B rays your skin needs to make vitamin D without exposing your skin to sun damage or increasing your risk of skin cancer.

The Bottom Line

Vitamin D deficiency is a real problem. Know what your vitamin D status is. If you have a normal level, be sure you’re taking steps to maintain it.



Medscape.com. “Vitamin D Deficiency: Implications Across the Lifespan”

Am J Clin Nutr. 2000; 72:690-3.

Harvard T.H. Chan School of Public Health. “Low Vitamin D: What Increases The Risk?”

Fungi.com.” Place Mushrooms in Sunlight to Get Your Vitamin D”

Medical News Today. “Nutrition / Diet

Vitamin D: Health Benefits, Facts, and Research


Related Articles By Cathe:

Winter Nutrition: How to Stay on Track with Your Diet All Winter Long

Is Vitamin D Important for Controlling Weight?

Can Vitamin D Improve Your Body Composition?

5 Factors That Negatively Affect Your Vitamin D Level

Can Vitamin D Improve Exercise Performance?


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