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We're told repeatedly to eat five servings of fruits and vegetables a day. It's advice that can help lower blood pressure, prevent stroke and reduce the risk of many cancers. And if you're a breast cancer survivor, eating more fruits and vegetables can help keep the cancer from coming back. But if "five a day" is good for you, is more better?

According to a randomized trial published in today's issue of The Journal of the American Medical Association, the answer is no. In a study of 3,088 women previously treated for early stage breast cancer, a major increase in fruits and vegetables - 12 servings a day - did not prevent additional breast cancers nor did it improve survival.

While literally hundreds of studies on food and nutrition have focused on cancer prevention, very few have examined the effect of lifestyle factors on cancer survival after diagnosis. When it comes to breast cancer recurrence, a handful of studies suggest that certain diet and lifestyle choices can improve survival. Studies have linked eating five daily servings of fruits and vegetables, regular exercise, increased fibre and reduced fat with a greater likelihood of recurrence-free survival.

In 2006, the U.S. Women's Intervention Nutrition Study (WINS), a randomized controlled trial that enrolled 2,437 postmenopausal women within one year of diagnosis of early stage breast cancer, found significant improvement in survival among women assigned to a low-fat diet (15 per cent of total calories or 33 grams of fat a day).

In the current Women's Healthy Eating and Living Study, researchers from the University of California, San Diego, assessed whether a diet very high in vegetables, fruit and fibre and low in fat would reduce the risks of recurrent breast cancer and death by any cause among women previously treated for early stage breast cancer.

The intervention group received a nutrition counselling program by telephone and cooking classes that promoted daily targets of 12 fruit and vegetable servings (five vegetable servings, 16 ounces of vegetable juice, and three fruit servings), 30 grams of fibre and 15 to 20 per cent of calories from fat.

Women in the comparison group received pamphlets recommending a daily diet with five servings of vegetables and fruit, more than 20 grams of fibre and less than 30 per cent of calories from fat.

After more than seven years of follow up, there was no difference between the two groups in either additional breast cancer or prolonged life. In both diet groups, 17 per cent of women were diagnosed with a breast cancer and 10 per cent died (more than 80 per cent of deaths were due to breast cancer). In other words, "five a day" is good for you, but "12 a day" doesn't offer extra protection.

The finding that reducing fat didn't benefit women in the intervention group is at odds with the earlier WINS results, which found benefit from a low-fat diet. However, in the current study, women assigned to the low-fat, high-fruit-and-vegetable group did not adhere to their fat-intake goal. At no time during the follow up did women in the intervention group achieve the target of 15 to 20 per cent of calories from fat. After four years, both groups consumed more than 27 per cent of daily calories from fat.

Additionally, women in the low-fat group of WINS lost weight over the study period. In the current study, women in both groups actually gained a little weight. Taken together, these findings support results from other studies suggesting obesity and weight gain after breast cancer diagnosis is associated with an increased risk of recurrence.

The notion that "five a day" is as good as it gets may come as a relief to women who find it challenging to add fruits and vegetables to every meal. But if you're already eating more than five servings of fruits and vegetables a day, there's no need to stop.

Exceeding the "five a day" advice might not prevent breast cancer recurrence, but it can lower blood pressure and, presumably, reduce the risk of stroke. Earlier randomized trials, called the Dietary Approaches to Stop Hypertension, demonstrated a potent blood pressure lowering effect from eating eight to 10 fruit and vegetable servings a day.

Based on the scientific evidence linking higher intakes of fruits and vegetables to protection from cancer and heart disease, this year's newly revised Canada's Food Guide advises Canadian women to consume seven to eight servings a day.

One serving is equivalent to half a cup (125 millilitres) of cooked or raw vegetables, one cup salad greens, one medium-sized fruit or half a cup of pure fruit or vegetable juice.

Leslie Beck, a Toronto-based

dietitian at the Medcan Clinic,

is on CTV's Canada AM every Wednesday. Visit her website

at Lesliebeck.com.

Breast cancer recurrence

An estimated 22,300 women in Canada will be diagnosed with breast cancer this year, according to the Canadian Cancer Statistics 2007 report. The following tips may help prevent recurrent cancer and improve your overall health.

More fruits and vegetables

Strive for at least five servings a day. Studies suggest that cruciferous vegetables (broccoli, Brussels sprouts, cabbage, cauliflower) and leafy greens are especially protective from breast cancer.

Reduce fat

Based on WINS trial findings, it's prudent to reduce your intake of dietary fat. Choose lean meats, poultry breast, legumes and non-fat dairy products. Use higher fat spreads and salad dressings sparingly.

Control your weight

Breast cancer survivors who are overweight or obese are more likely to have their cancer recur compared with thinner survivors. Women are advised to keep their body mass index in the range of 18.5 to 25 and prevent weight gain.

Be active

Moderate exercise has been shown to improve breast cancer survival. In a study published last month, walking for 30 minutes six days a week - combined with eating five or more servings of fruits and vegetables - reduced breast cancer death by 46 per cent.

Drink green tea

There's preliminary evidence that drinking three to five cups of green tea a day may help prevent breast cancer recurrence in early stage cancers.

Leslie Beck

lesliebeck.com