Vitamin D3
The “sunshine vitamin” for healthy bones and immunity
Do you get 10-15 minutes of exposure to sunlight everyday? If not, you may have a deficiency of vitamin D. Vitamin D is produced in your skin when you are exposed to the ultra violet (UV) frequencies found in natural sunlight. Unfortunately, many people get very little exposure to natural sunlight and, as a result, may wind up deficient in vitamin D.
Perhaps you work indoors. In the winter, many people in Northern climates drive to work in the dark, work all day under artificial lights and then drive home in the dark. Sunlight filtered through a window will not produce vitamin D. Cloud cover and smog reduce UV light and vitamin D production.
Vitamin D is primarily known for its role in promoting calcium absorption from the intestinal tract. It helps to maintain adequate levels of calcium and phosphorus in the blood to enable the mineralization of bone. Without sufficient vitamin D, bones become thin, brittle or misshapen. A severe deficiency produces the disease known as rickets in children and osteomalacia in adults. Vitamin D is needed to prevent osteoporosis in the elderly, too.
However, the benefits of vitamin D do not end with the role it plays in maintaining proper calcium and phosphorous levels for bone health. Vitamin D also affects the immune system. It promotes phagocytosis (anti-tumor activity) and helps modulate the immune system. Some evidence suggests it may have a role in protecting the body against cancer.
Insufficient levels of vitamin D may also be linked to an increased susceptibility to other chronic diseases. These include high blood pressure, tuberculosis, periodontal disease, multiple sclerosis, chronic pain, depression, schizophrenia, seasonal affective disorder, peripheral artery disease, type 1 diabetes and several autoimmune diseases. There is debate about whether vitamin D plays a protective role in preventing heart disease, but heart attacks are more frequent in winter and are lowest in summer in temperate climates. In addition, cholesterol levels were found to be lower in gardeners during the summer months.
Very few foods in nature contain vitamin D. It is found in fish, such as salmon, tuna, and mackerel and fish liver oils. These are the best sources, but smaller amounts are found in beef liver, cheese and egg yolks. Vitamin D3 is the form found in these foods.
The U.S. Dietary Reference Intake for adequate intake of vitamin D for men and women aged 19–50 is 5 micrograms per day, which is 200 IU per day. This recommendation doubles for men and women aged 51-70 (400 IU per day) and triples for people over the age of 70 (600 IU per day).
However, during winter months at higher latitudes or in the absence of exposure to sunlight, the need for Vitamin D is much higher than these basic amounts. In the absence of exposure to UV from sunlight, children probably need 1000 IU of vitamin D per day and adults need four times that amount (4000 IU).
Diary products are commonly fortified with vitamin D2 or D3. Other foods that may be fortified with a form of vitamin D include margarine, breakfast cereals and bread. A glass of milk typically contains 100 IU of vitamin D, but many people do not consume dairy products due to milk allergies, lactose intolerance or strict vegetarian diets. As a result, many people wind up being deficient.
Deficiencies can also occur because of liver or kidney disorders which interfere with the conversion of the vitamin or rare hereditary disorders. However, the most common cause of deficiency is lack of exposure to sunlight and lack of dietary intake.
It is interesting that people are being encouraged to use sunscreen to protect their skin from UV radiation as vitamin D deficiency may be a contributing factor to the development of skin cancer. A sunscreen with a sun protection factor (SPF) rating of only 8 inhibits more than 95% of vitamin D production in the skin. Following a campaign encouraging Australians to “cover up” to protect against skin cancer, there was an increase in vitamin D deficiency. People who wear clothing that protects all parts of the body from exposure to sunlight have also been shown to be at risk for vitamin D deficiency.
One billion people in the world are currently Vitamin D deficient. Obese individuals often have lower levels of vitamin D and are at increased risk for deficiency. Cases of rickets are still occurring periodically in the United States, particularly among African American infants and children. This severe vitamin D deficiency usually occurs in cases of prolonged, exclusive breast-feeding of dark-skinned infants whose mothers are vitamin D deficient. The use of sunscreen on children and the increase of indoor activities with limited exposure to sunlight are also causing vitamin D deficiencies in children.
Suggested Use
NSP’s Vitamin D3 contains 2,000 IU natural vitamin D3 derived from lanolin harvested from the wool fat of sheep from New Zealand and Australia. These animals are certified BSE-free. Take 1–2 tablets daily with a meal.
Selected References
www.vitamindcouncil.org/
http://ods.od.nih.gov/factsheets/vitamind.asp
