Fondly referred to as the sunshine vitamin, vitamin D is produced when the body is exposed to sunlight. However, for those who live in areas with cold winters, it can be tough to get enough of the sunlight the skin needs to make this important vitamin.
Foods that contain vitamin D include:
- Fatty fish, like tuna, mackerel, and salmon
- Foods fortified with vitamin D, like some dairy products, orange juice, soy milk, and cereals
- Beef Liver
- Egg yolks
However, getting the right amount of vitamin D doesn’t depend on the foods you eat. To get enough vitamin D you need to expose your skin to sunlight regularly and you may also need to take a supplement (D3 is usually recommended).
Vitamin D has long been recognized in playing a critical role in absorbing calcium, which is vital in developing and keeping bones healthy. Children who don’t get enough vitamin D can get a condition called rickets, where their bones don’t form properly because they don’t have calcium to harden. In older adults, vitamin D deficiency can lead to a condition called osteomalacia, where the bones weaken. This can cause pain and be accompanied by muscle weakness. Mild deficiency may contribute to osteoporosis in older adults. In addition, vitamin D deficiencies are generally associated with weak muscles, soft bones, excess sweating, fatigue, and the inability to think clearly (jenreviews).
In recent years, research shows that vitamin D may do much more than just keep bones strong.
Low Vitamin D Linked to Chronic Headaches
In a recent study (the Kuopio Ischemic Heart Disease Risk Factor Study), data on 2600 middle-aged men showed that those with the lowest levels of serum 25-hydroxyvitamin D (25[OH]D) were more than twice as likely to report having chronic headaches as those who had the highest vitamin D levels.
"This increased risk was only seen in the lowest quartile. But it was surprisingly strong for the men with very low vitamin D status," lead author Jyrki K. Virtanen, PhD, adjunct professor in nutritional epidemiology at the University of Eastern Finland in Kuopio, told Medscape Medical News in an article published on January 19, 2017.
In addition, reports of chronic headache were significantly more frequent in months other than the summer months (June through September).
Low vitamin D level predicts CV morbidity, mortality in type 2 diabetes
In a Swedish study, older adults with type 2 diabetes and low 25-hydroxyvitamin D levels were more likely to experience a cardiovascular event versus those with higher vitamin D levels.
“The significant association was consistent when adding conventional [CV] risk factors, physiological variables including [parathyroid hormone] and previous [CVD] into the analyses,” Maria Samefors, PhD, of the department of medical and health sciences at Linköping University, Sweden, and colleagues wrote. “This finding is clinically significant because a 20-nmol/L increase in serum 25-(OH)D3 was associated with a 37% decrease in risk [for CV] morbidity and mortality, a result that is emphasized by the high prevalence of vitamin D deficiency in our participants.”
Vitamin D May Slow Weight Gain
Vitamin D supplements may help those who are trying to lose weight. In a study published in the American Journal of Clinical Nutrition, people taking a daily calcium and vitamin D supplement were able to lose more weight than subjects taking a placebo supplement. The scientists said the extra calcium and vitamin D had an appetite suppressing effect.
Vitamin D May Ensure a Healthy Pregnancy
Did you know that an expectant mother with a vitamin D deficiency is at risk in her first trimester of giving birth to a baby with extremely low birth weight? These babies are also born with a higher risk of developing conditions such as heart disease and hypertension later in life. Vitamin D 2 and 3 are the most important compounds for human development, which is why adequate levels of vitamin D are so important for pregnant women (jenreviews).
Vitamin D May Ward Off Depression
Research has also shown that vitamin D might play an important role in regulating mood and warding off depression. In one study published in the Journal of Internal Medicine, scientists found that people with depression who received vitamin D supplements noticed an improvement in their symptoms.
Vitamin D Deficiency
A vitamin D deficiency = less than 20 ng/ml (40 nmol/L). At this range, vitamin D is inadequate for bone health and disease risk in general. A simple blood test can determine vitamin D deficiency.
In general, the following people may be at risk for vitamin D deficiency:
- Older people
- Persons with dark skin
- People who are obese or have kidney or liver disease
- People who do not get enough direct sun exposure
Recent research indicates that you need more vitamin D than was once thought. Normal blood serum levels range from 50 to 100 micrograms per deciliter. Depending on your blood level, your vitamin D intake needs may be increased.
The Institute of Food and Agricultural Sciences has reported the following intake recommendations.
The recommended IUs for vitamin D are:
- children and teens: 600 IU
- adults up to age 70: 600 IU
- adults over age 70: 800 IU
However, other organizations recommend that you take more. For example, the Vitamin D Council recommends 1000 IU’s of vitamin D per 25lbs each day. A healthy human body utilizes about 3000-5000 IU of vitamin D per day.