Vitamin D Has More Benefits Than Previously Thought
Vitamin D has long been known as an important vitamin for bone health, preventing conditions such as osteoporosis and rickets. More recently, research suggests that vitamin D may also protect against conditions such as cancer, heart failure, diabetes, respiratory tract infections, and autoimmune disease.
Many Americans have low vitamin D or a vitamin D deficiency. The human body produces vitamin D in large amounts when the skin is exposed to ultraviolet B rays in sunlight. Vitamin D can also be absorbed from vitamin D–fortified foods such as dairy products, some orange juice, and cereals. Some foods such as fatty fish, beef liver, and egg yolks naturally contain some vitamin D, but it is difficult to get enough vitamin D just from consuming these foods.
Low mood or seasonal affective disorder (SAD), in which people feel depressed during winter periods of limited exposure to sunshine, have been linked to low vitamin D.
Other symptoms of low vitamin D vary but can include pain in the joints, bones, or muscles; fatigue; and breathing problems.
Editor’s Note: A few small studies have suggested that 1,500 IU per day of vitamin D supplements can help depressed mood, even in those with normal vitamin D levels. Several studies have indicated that children or adolescents with psychiatric disorders are especially likely to be vitamin D–deficient. Another study found that higher amounts of vitamin D (4,000 IU) could improve cognition in healthy volunteers more than lower doses could. Vitamin D also improved cognition in people with multiple sclerosis and in those with the autoimmune disease Hashimoto’s thyroiditis.
