The spell of half-decent weather we've had of late is a sure sign that spring is well into its stride and summer is just around the corner. Personally, I greet this time of year with relish. For as long as I can remember, sunshine has had a strong allure for me and I generally take every opportunity to get dosed up on what can often seem to be only too precious a commodity. Anecdotal evidence suggests I'm not alone in my love of the sun; I don't remember meeting anyone who confessed to preferring grey skies over blue, and the sunny weather certainly seems to bring us out in droves. What is it they say about mad dogs and Englishmen?

Yet, while we may feel better sunning ourselves, this most innocent of pleasures is seemingly not without risk. Doctors and scientists have made us only too aware of the link between sunlight and skin cancer, and the spectre of malignant melanoma in particular looms large in many of our minds. The impression is that when we get out in the sun, we really are playing with fire. Yet, not all research suggests that sunlight is the dark force it's often made out to be. Recent studies, for instance, have found that while sun exposure appears to increase the risk of skin cancer, it may help to protect us against other common and important forms of cancer. Some researchers are suggesting that getting more sun, rather than putting us at increased risk of cancer, actually does quite the reverse.

Skin cancer affects about 50,000 Britons every year, the great majority of which are what are known as basal cell and squamus cell carcinomas (carcinoma is another name for cancer). For the most part, these forms of cancer are usually curable with conventional treatment, and are rarely life-threatening. About 10 per cent of skin cancers are of the malignant melanoma type. Unlike the more common forms of skin cancer, malignant melanoma is not so amenable to treatment, and kills about 1,500 Britons each year. There is evidence that burning and/or occasional exposure to intense sunlight, particularly in childhood, increases the risk of malignant melanoma. No wonder then that skin and cancer specialists urge us to be wary of the sun.

However, there are two sides to every coin, and sunlight is no exception. While sun exposure may increase the risk of skin cancer, it is also believed to have a slew of health-giving properties. For one thing, ultraviolet radiation from the sun increases the formation of vitamin D in the skin and this nutrient has important roles to play in the health of the bones, muscles and immune system. Perhaps even more importantly, vitamin D appears to have cancer-protective qualities, too. There is evidence from test-tube and animal experiments that shows vitamin D has the ability to combat the development and spread of cancerous tumours.

While some foods, notably oily fish, eggs, butter and milk, provide us with some vitamin D, it is actually sunlight that meets most of our needs in this department. Increasing evidence suggests that sunlight reduces the risk of several types of cancer, and the smart money is on vitamin D as the critical factor. A study published last month in the journal Cancer found sunlight exposure afforded significant protection from cancers of the breast, colon and ovary. Other cancers that showed this same association with sunlight, though to a lesser degree, included those affecting the bladder, womb, oesophagus (food pipe), rectum and stomach. Another study, which appeared last year in the Lancet , found that sunlight seemed to offer considerable protection against prostate cancer.

Evidence dating back over the past 20 years suggests that shying away from the sun may actually put us at increased risk of cancers. Just a 10 per cent reduction in average sunlight exposure has in some studies been found to be associated with about a 10 per cent increase in risk of both breast and colon cancer. It appears that the extra deaths induced by rationing our time in the sun would more than outweigh the lives saved through malignant melanoma prevention.

For those keen to protect themselves from skin cancer, particularly if there has been any history of this, then the best advice is to avoid the sun. However, bearing in mind what we are learning about the effects of sunlight on other forms of cancer, then my belief is that the medical establishment's party line about the hazards of the sun needs some tempering. While exposing unprotected skin to the hot sun and burning ourselves to a crisp is certainly not advised, the evidence does suggest that, as long as we are sensible about it, getting out in the sun is likely to do us more good than harm. I, for one, won't be hesitating to get my fair share of sun this summer.

Dear John

I suffer from lumpy breasts which can get quite tender before a period. My gynaecologist says I have fibrocystic breasts, but that these will get better after the menopause. At 37, I'm keen to be pro-active. Do you have any advice for me?
Linda Coughlan, north London

A Fibrocystic breast disease (FBD) is characterised by the presence of multiple cysts (fluid-filled pockets) in the breasts. It is thought to affect about 30 per cent of pre-menopausal women. The condition is believed to be related to raised levels of the hormone oestrogen in the body, which is why it usually subsides after the time of menopause (when oestrogen levels fall). Although the cysts characteristic of FBD are benign, any woman with a lump in her breast should see her doctor.

It seems the symptoms of FBD are made worse by the consumption of caffeine and caffeine-like substances found in coffee, tea, caffeinated soft drinks and chocolate. Studies show complete abstinence from these foodstuffs can be helpful in controlling the symptoms of FBD. In addition, certain natural substances may help. Studies show vitamin E is effective, and you might try taking 400-600 IU of vitamin E each day to see if this helps. Another nutrient to try is evening primrose oil. This has anti-inflammatory and hormone-balancing effects which may help alleviate your symptoms. The normal recommended dose is 1g three times a day.

Nutrition news: Fat can be good for you too

Eating a diet high in fat is likely to increase the risk of heart disease in the long term. However, new evidence suggests that fat has important implications for the heart in the short term, too. In a study published in the Annals of Internal Medicine , researchers compared the effects of two 1,200-calorie meals with differing fat content on the amount of blood getting through to the heart muscle. A meal containing a modest 10g of fat had no effect on blood supply to the heart after five hours. However, a meal loaded with 100g of fat (about the amount you'd get in a fast-food meal plus dessert) reduced the blood supply to the heart by about a fifth.

In theory, a high-fat meal might trigger angina (heart pain) or even a heart attack in those with heart disease.

· If you have any issues you would like Dr John Briffa to address in this column, please contact him by email on john.briffa@observer.co.uk. Please note that Dr Briffa cannot enter into any personal correspondence.