You may well be both sick and tired if you are battling an insufficient level of this critical hormone and so-called sunshine vitamin. The latest research indicates that vitamin D continues to be a hot topic among both experts and the general public.
Vitamin D is necessary to help regulate and maintain calcium and phosphorus levels in the blood and to work with these and other minerals to support and promote bone and teeth health and viability. This fact, along with the finding that more than 40 percent of adults in the United States have a deficiency of this vitamin, suggests we need to pay much more attention to vitamin D, not only in for its role in bone health but for other possible health benefits.
Do you have a vitamin D deficiency?
Although more than 40 percent of adults in the US are said to be vitamin D deficient, the percentage is significantly higher in certain groups: about 82 percent among African Americans and 69 percent among Hispanic people, believed to be from skin tone and the way they convert sunlight into vitamin D. Some of the signs and symptoms of a vitamin D deficiency can include breathing problems, low mood, fatigue, painful joints, and pain in the muscles and/or bones.
What exactly is a vitamin D deficiency?
That depends on who you ask. First, however, you need to have your vitamin D levels checked using a simple blood test. Your doctor will test your 25(OH)D level, which is commonly referred to as a vitamin D test.
According to a recent international report in Anticancer Research, the recommended target levels for vitamin D range from 25 to 50 nmol/L (10 to 20 ng/mL), which corresponds to a daily intake of vitamin D of 400 to 800 International Units (or 10 to 20 micrograms). Not everyone agrees, however.
- Vitamin D Council: 40 to 80 ng/mL, with 50 ng/mL being ideal. To reach and maintain that level, the Council recommends that adults take 5,000 IU daily of vitamin D.
- Endocrine Society: 30 to 100 ng/mL. To achieve and keep a level of 30 ng/mL, the Society recommends taking 2,000 IU/daily of vitamin D.
- Food and Nutrition Board: greater than 20 ng/mL. The Board recommends taking 600 IU daily for a level of 20 ng/mL.
In addition, you should know when you have taken too much vitamin D: the toxic level is generally regarded as more than 150 ng/mL. The upper limit for supplementation for adults is 10,000 IU for both the Vitamin D Council and the Endocrine Society and 4,000 IU for the Food and Nutrition Board.
Where to get vitamin D?
Vitamin D is available through three sources: certain foods, direct contact with sunlight, and supplementation. The number of foods with an excellent or good amount of vitamin D is rather small: fortified milk and plant beverages, beef liver, egg yolks, mushrooms, oily fish, and fortified breakfast cereals.
Sunlight is an excellent way for your body to produce the vitamin D it needs, but you should be exposed to sunlight (without sunscreen) for about 20 minutes per day for four days a week year-round for that benefit. (The rest of the time, it is important to protect your skin with a mineral-based sunscreen such as one from our sponsor Goddess Garden.) This is generally sufficient for people who are fair-skinned, but longer times are needed for those with darker skin. Several other factors are also involved when it comes to sun exposure and vitamin D production.
Another way is through supplementation. Because so many people find it difficult to get the vitamin D they need via food and/or sunlight (especially in the northern hemisphere), taking a supplement is often a reliable alternative. Vitamin D3 is recommended rather than vitamin D2 because it is the type your body produces when it is exposed to the sun.
Why take vitamin D?
In addition to providing critical support for bone and teeth health, vitamin D:
- Helps support the immune system, nervous system, and brain function.
- Regulates insulin levels and helps with the management of diabetes.
- Supports cardiovascular and respiratory health.
- Has an impact on the expression of genes that are involved in the development of cancer.
Numerous studies have indicated that low levels of vitamin D are associated with a variety of serious health problems. All of the research is not yet in, but scientists are exploring the effects of vitamin D supplementation in people with insufficient or deficient levels and the following health challenges:
- Asthma and allergic diseases: Low vitamin D is associated with greater risk and severity of allergic diseases, atopic dermatitis, and eczema in children.
- Depression: Some research suggests vitamin D can help relieve depressive symptoms in individuals with clinically significant depression.
- Colds and other respiratory illnesses: Individuals who are deficient in vitamin D and who take a supplement may develop fewer cases of cold or flu. A review of 25 controlled trials noted a 12 percent reduced risk for respiratory infections after the supplement was taken, although not every study showed this benefit.
- Cardiovascular events: A limited amount of evidence indicates that maintaining adequate vitamin D levels can reduce the risk of cardiovascular events, such as stroke and heart failure.
- Cancer: Conflicting findings abound when it comes to the role of vitamin D in helping prevent cancer, but study results have been promising when it comes to breast, colon, ovarian, and prostate cancers.
[Editor's Note: If you are looking for a healthy snack that contains vitamin D, Made Good makes products (granola, granola bars, minis, crispy squares, and cookies) that have one hidden serving of vegetables, including shiitake mushrooms, and provide 20% of the recommended level of vitamin D.]
Al Mheid I et al. Vitamin D and cardiovascular disease: is the evidence solid? European Heart Journal 2013 Dec; 34(48): 3691-98
Forrest KY, Stuhldreher WL. Prevalence and correlates of vitamin D deficiency in US adults. Nutrition Research 2011 Jan; 31(1): 48-54
Garland CF et al. The role of vitamin D in cancer prevention. American Journal of Public Health 2006 Feb; 96(2): 252-61
Martineau AR et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ 2017; 356:i6583
Pilz S et al. Vitamin D: current guidelines and future outlook. Anticancer Research 2018 Feb; 38(2): 1145-51
Searing DA, Leung DYM. Vitamin D in atopic dermatitis, asthma, and allergic diseases. Immunology and Allergic Clinics of North America 2010 Aug; 30(3): 397-409
Shaffer JA et al. Vitamin D supplementation for depressive symptoms: a systematic review and meta-analysis of randomized controlled trials. Psychosomatic Medicine 2014 Apr; 76(3): 190-96
Vitamin D Council. Testing for vitamin D.