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Not Getting Enough Vitamin D in Your Diet May Impair Muscle Function

An array of vitamin-D-rich foods, such as milk, cheese, eggs, salmon, and mushrooms.

Yulia Gusterina / Getty Images

Key Takeaways

  • A new study finds that vitamin D deficiency may cause muscle impairment.
  • Many people do not get enough vitamin D in their diets, leading to a deficiency.
  • There are several ways people can increase their vitamin D levels—from eating more vitamin D-rich foods to supplementation and sunlight exposure.

Vitamin D is a well-known supporter of bone health and calcium absorption. And a new study shows it's likely important for muscle function as well.

Researchers from Australia and the United Kingdom conducted a study in mice that suggests inadequate amounts of dietary vitamin D may impair muscle function. The study will be published in the Journal of Endocrinology in May.

Why We Need Vitamin D

"Vitamin D plays an important role in maintaining skeletal health and even body composition," Heather Hanks, MS, a nutritionist in Michigan, tells Verywell. "However, vitamin D is needed for so much more than this. It's imperative for a properly functioning immune system, which is so important to maintain now more than ever."

As important as the nutrient is for us, vitamin D deficiency is common. According to a 2011 study published in the journal Nutrition Research, around 40% of participants in a survey in the U.S. were deficient in vitamin D.

How Much Vitamin D You Need

The recommended dietary allowances (RDA) for vitamin D are set by the National Institutes of Health (NIH) Office of Dietary Supplements.

How much vitamin D you should aim to get per day depends on your age:

  • 0-12 months old: 10 mcg
  • 1-70 years old: 15 mcg
  • Older than 70 years old: 20 mcg

The body needs vitamin D to function properly—not getting enough can cause a host of health problems. "No vitamin requires more whole-body participation than vitamin D, the skin, bloodstream, kidneys, and liver all contribute to the formation of fully active vitamin D known as D3," Dave Coast, a Los Angeles-based registered holistic nutritionist, tells Verywell. "I'm not too surprised to see that a lack of vitamin D resulted in reduced lean muscle tissue since it directly affects bone health."

Energy Levels and Muscle Function Were Impacted

The researchers used a mouse model to compare the effects of the two diets. All of the mice were weighed at the beginning of the study, then put into two groups: one that would have a diet with enough vitamin D, and the other on a vitamin D-deficient diet.

The mice were weighed again at one, two, and three months. The researchers also collected tissue samples from the mice at each interval to test if the skeletal muscle mitochondrial respiration was affected by vitamin D levels.

Diet-induced vitamin D deficiency reduced skeletal muscle mitochondrial respiration in mice. The finding suggests that muscle function might be impaired by inadequate levels of vitamin D in the diet.

However, there were other measurements that did not change between the two groups of mice. For example, the researchers wrote that there was no difference between the "vitamin D-replete and -deplete groups in body weight, lean mass, fat mass or food intake at the 3-month time point."

The body's energy levels might also be affected by vitamin D deficiency. The researchers wrote that "reductions in physical performance following vitamin D deficiency may also result in reduced daily activity levels which in turn could influence body composition and energy metabolism."

Vitamin D and COVID

Some early research has suggested that vitamin D might play a role in how you fare if you get COVID-19. A 2020 study published in the Journal of Clinical Endocrinology & Metabolism found that patients hospitalized with COVID-19 were more likely to be vitamin D deficient than people in the general population. But experts say more research is needed to examine this potential link.

How to Get More Vitamin D

If your vitamin D levels are low, you aren't alone. Luckily, there are several ways to increase your levels of vitamin D.

Supplements

You can raise your vitamin D levels by taking supplements. Coast says that "taking calcium, magnesium, and vitamin D together is ideal for bone health."

If you have certain chronic conditions, Coast adds that "vitamin D is sometimes recommended with vitamin A for the treatment of asthma, muscle spasms, and arthritis."

Diet

According to Susan Bowerman, MS, RD, the senior director of Worldwide Nutrition Education and Training at Herbalife Nutrition, vitamin D deficiency is usually related to a person's diet, and that "most people in the U.S. consume less vitamin D than they should, in part because not many foods naturally contain this important nutrient."

Bowerman tells Verywell you should consider consuming more of the following foods and drinks, since all are good sources of vitamin D:

  • Fatty fish is one of the best dietary sources of vitamin D.
  • Beef liver is a non-fish meat source of vitamin D.
  • Cheese and egg yolks. While these foods contain some vitamin D, people may limit dairy and eggs in their diets because they are concerned about the saturated fat and cholesterol content.
  • Mushrooms can be another source of vitamin D, depending on how they are cultivated.
  • Fortified milk is the primary source of vitamin D for most people in the United States. Some milk alternatives are fortified with vitamin D at levels that can rival fortified dairy milk. With any fortified milk, you might need to have more than one serving to get the recommended amount of vitamin D.
  • Breakfast cereals and other foods such as orange juice and yogurt can also be fortified with vitamin D.

Sunshine

While dietary changes and supplements can help, you can also boost your vitamin D levels for free by spending more time outside in the sun. "Most sources suggest that anywhere from 5 to 30 minutes of sun exposure to the face, arms, hands, and legs a few times a week should be adequate," Bowerman says.

What This Means For You

Your healthcare provider can use a blood test to determine if you are deficient in vitamin D. There are many ways you increase your vitamin D levels, like getting more sunlight and adding vitamin D-rich foods like fatty fish and fortified milk to your diet. If needed, you can also take supplements.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Ashcroft SP, Fletcher G, Philp AM, et al. Diet-induced vitamin D deficiency reduces skeletal muscle mitochondrial respiration. J Endocrinol. 2021 May;249(2):113-124. doi:10.1530/joe-20-0233

  2. Forrest KYZ, Stuhldreher WL. Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res. 2011 Jan;31(1):48-54. doi:10.1016/j.nutres.2010.12.001

  3. National Institutes of Health Office of Dietary Supplements. Vitamin D. Updated: March 26, 2021.

  4. Hernández JL, Nan D, Fernandez-Ayala M, et al. Vitamin D status in hospitalized patients with SARS-CoV-2 infection. J Clin Endocrinol Metab. 2021 Mar;106(3):e1343-e1353. doi:10.1210/clinem/dgaa733