Vitamin D (Cholecalciferol) is a fat-soluble vitamin found in food. Technically it is a hormone and it is produced in the body when the skin is exposed to the ultraviolet (UVB) rays in sunlight. Spending a few minutes outside each day should supply you with all the vitamin D you need.  However sun exposure must involve at least some direct exposure to skin (hands, face, arms, etc.). Your clothing blocks the ultraviolet light that triggers vitamin D formation.  Most people, including infants, require little or no extra vitamin D from food when regularly exposed to sunlight when the sun is high in the sky. Bright sunlight is not necessary; even a cloudy summer day will stimulate formation of some vitamin D in the skin, while a short summer holiday in the open air will increase blood levels of the vitamin by two or three times the amount.

The basic function of vitamin D is to aid the body’s absorption of calcium, helping build strong bones and healthy teeth. It may also protect against some forms of cancer. Studies have also shown that it is important in the prevention of osteoporosis, a disease that causes porous bones. Without sufficient vitamin D the body cannot absorb sufficient calcium from food.

Vitamin D deficiency can be caused by a lack of vitamin D in the diet or by inadequate exposure to sunlight. Deficiency is seen more often in colder climates, or where weather dictates that the body is well covered by clothes.  It can also be found in countries where women are completely covered. A pregnant woman with vitamin D deficiency may develop osteomalacia, (soft bones) and the new-born have a high risk of developing rickets. Because breast milk does not contain large amounts of vitamin D, breast fed infants who are not exposed to sufficient sunlight may develop rickets and usually require supplements. The body’s ability to manufacture vitamin D declines with age so vitamin D deficiencies are common in older people. The deficiency occurs in older people because their skin, when exposed to sunlight, produces less vitamin D. Also, older or sick people who tend to be house-bound need to make sure they are receiving sufficient vitamin D in their diet.  Signs of deficiency include bone pain and muscle weakness. The diagnosis of rickets or osteomalacia caused by lack of vitamin D is based on symptoms and the appearance of bones on x-rays, and a low level of vitamin D by-products in the blood.

The cooler winter months are a great time to take a walk and get some sunshine and a natural source of vitamin D. You don’t need to stay in the sun for long to build up vitamin D. For most of us, 10 minutes exposure, wearing normal clothes — exposing just a bit of hands, arms and face — should supply you with all the vitamin D you need.

If you feel you may be not be getting sufficient sunlight then look at your diet. The few foods that contain vitamin D include egg yolks, butter, vitamin D-fortified milk, fish liver oil, breast milk, and infant formula. In addition to breast milk and formula, calcium is found in dairy products, sardines, canned salmon, green leafy vegetables, and tofu. Pure vegetarians may use supplements instead of eggs and dairy as sources for both calcium and vitamin D. If you feel you may need a vitamin D supplement you should consult your Doctor or dietitian. My healthy eating guide is a good source of information on diet: Send an e-mail to [email protected] for a copy.

* Regulates calcium levels in the bones

* 90% comes from sunlight

* 10% comes from food

* Food sources — oily fish, eggs, fortified cereals

* Breast fed children may need supplements

You don’t need to stay in the sun for long to build up vitamin D stores in the body and you can benefit from the sunrays even on a cloudy day. For most of us, 10 minutes exposure, wearing normal clothes — exposing just a bit of hands, arms and face — should supply you with all the vitamin D you need. But those at risk or with a history of skin cancer or with sun sensitive skin conditions should check with their dermatologist first.

I am feeling very tired and feel I may be lacking in iron and anemic. Can you suggest a supplement to take? 

— Lula

Don’t diagnose yourself. If you have symptoms that you are concerned about, the first thing you should do is see a trained doctor who will make a skilled diagnosis. Your doctor is your body’s best friend and modern diagnostic techniques prevent disease. Your doctor will tell you whether or not you need an iron supplement, and how much you need to take.

— Alva