Sunshine on My Shoulder (Makes Me Happy)

Most public health messages have focused on the hazards of too much sun exposure. But there is some sunny news about the sun.

Sunlight increases the body’s vitamin D supply. In seniors, vitamin D protects against osteoporosis, a disorder in which the bones become increasingly brittle. Vitamin D also protects against cancer, heart disease and other maladies.

But there are other benefits to a daily dose of sunlight.

Seasonal affective disorder (SAD) is a form of depression that affects people when they don’t get enough sunlight. Remember the John Denver lyrics: “Sunshine on my shoulders makes me happy ... Sunshine almost always makes me high.” Psychiatrists often recommend that, if you are depressed, you should spend a half-hour a day in the sun.

Melatonin is a hormone produced at night that makes you sleepy. Sunlight cuts off the production of melatonin in your body and helps you to feel tired when you should be — at bedtime. Getting about 15 minutes of sunlight every morning tells your body it’s no longer night. So sunlight is a sleep aid.

Exposure to sun appears to suppress an overactive immune system. This might explain why sunlight may help with autoimmune diseases such as psoriasis and lupus. One study also suggests it might help alleviate asthma.

A study published in the Journal of the American Medical Association showed that Alzheimer’s patients exposed to sunlight got better scores on a mental exam and had fewer symptoms of depression than patients exposed to dim light.

Some scientists are concerned that there is too much emphasis on preventing skin cancers and not enough on the danger of more lifethreatening cancers such as lung, colon and breast cancers affected by insufficient sunlight.

Many studies have shown that cancerrelated death rates decline as you move toward lower latitudes.

“As you head from north to south, you may find perhaps two or three extra deaths [per hundred thousand people] from skin cancer,” says Reinhold Vieth, a nutrition professor emeritus at the University of Toronto. “At the same time, though, you’ll find 30 or 40 fewer deaths for the other major cancers. So when you estimate the number of deaths likely to be attributable to UV light or vitamin D, it does not appear to be the best policy to advise people to simply keep out of the sun just to prevent skin cancer.”

A recent study published in the Archives of Internal Medicine showed that those with the lowest vitamin D levels have more than double the risk of dying from heart disease and other causes over an eight-year period compared with those with the highest vitamin D levels.

How much sun do you need? The amount of vitamin D you need each day depends on your age. The Food and Nutrition Board (a national group of experts) recommends that everyone from 1-70 years take in 600 International Units a day. Adults 71 and older should consume 800 IU.

Q. I’m 68 years old, and I want to know how much vitamin D you need to be healthy.

The Office of Dietary Supplements in the National Institutes of Health recommends the following daily dietary allowances: 400 IU for children under one year; 600 IU for everyone 1–70 years old, and 800 IU for everyone more than 70 years old.

The recommended upper limit for vitamin D is 2,000 IU a day. Vitamin D can be toxic when taken in higher doses. Vitamin D is included in most multivitamins, usually in strengths from 50 IU to 1,000 IU. Vitamin D toxicity is rare. There is a greater risk of poisoning if you have liver or kidney conditions or take some diuretics.

There are different forms of vitamin D. The major forms — the ones important to humans — are vitamin D2 and vitamin D3.

Plants synthesize vitamin D2. We get vitamin D in our diet. Very few foods in nature contain vitamin D. It is found in eggs, dairy products, fish, oysters and cod liver oil. Foods such as milk may be fortified with vitamin D2 or D3. Fortified foods provide most of the vitamin D in the American diet.

Vitamin D3 is synthesized in human skin when it is exposed to sunlight. About 10 minutes of daily exposure to the sun is considered enough to prevent deficiencies.

Vitamin D’s primary job is to maintain normal amounts of calcium and phosphorus in your blood. Vitamin D helps keep your bones strong. Research suggests that vitamin D may protect us not only from osteoporosis (loss of bone density) but also from high blood pressure, cancer, heart disease, diabetes, multiple sclerosis and psoriasis.

Populations at high risk for vitamin D deficiencies include the elderly, obese individuals and people with limited sun exposure. Osteomalacia — also known as adult rickets — is found in older patients deficient in vitamin D. Osteomalacia causes bone and muscle weakness.

People older than 50 are at increased risk of developing vitamin D insufficiency. As people age, the skin cannot synthesize vitamin D as efficiently, and the kidneys cannot convert vitamin D to its active hormone form.

Recent studies indicate that vitamin D reduces the risk of falling, which is especially dangerous for seniors. However, to obtain the benefits of the vitamin, you must take 700 to 1,000 IU a day. These studies buttress other research showing that vitamin D improves strength, balance and bone health in the elderly.

Each year, one-third of people 65 and older and one-half of people 50 and older fall at least once. Almost one-tenth of these falls put their victims in an emergency room — many seniors who fall end up in nursing homes.

Fred Cicetti is a freelance writer who specializes in health. He has been writing professionally since 1963. Before he began freelancing, he was a reporter and columnist for three daily newspapers in New Jersey. If you would like to ask a question, write to fred@healthygeezer.com.