How important are five colored veggies?


In any group of people there will be someone who “knows” what vegies you should eat for good health, cancer prevention and other topical (mis)conceptions.

However, what we eat is something that has fascinated us for centuries. We have made rituals and even fetishes out of eating and drinking, and the oldest gourmet group in the world, the Chaine des Rotisseurs, is still going and that began in 1248 AD. That’s a long lunch!

With our tentative forays into ‘real’ science, our dietary habits have also been scrutinized and many claims made for modifying the kind of food we eat and what we drink. This in turn, has produced legions of people who swear by various foods which will cure everything from falling hair to falling arches!

Of course, it is very difficult to ‘prove’ that by taking Peruvian ground nuts or similar items, that ‘something’ (usually cancer) does not happen. Even more outrageous are the claims that some herb, poppy or whatnot can actually ‘cure’ cancers. Is it all just poppycock?

To be able to prove these claims needs medical science to look at a large group, or population, and compare the cancer experience with another similar large group or population. Ideally, the two groups are matched for age/sex/ethnicity/working environment, location etc. You get no worthwhile results comparing Welsh coalminers with sub-Saharan Africans, for example, to go to extremes.

Some results of a 15+ year study in Australia were presented at the CSIRO Prospects for Cancer Prevention Symposium. The findings emerged from the Cancer Council’s Melbourne Collaborative Cohort Study, an ongoing research project involving 42,000 Australians who have been monitored since 1990. A large group.

Looking at dietary habits and the cancer connection, the director of the CSIRO’s Nutrition Clinic, said there was “zero evidence” that eating fruit and vegetables (no matter what colors) could protect against cancer.

This to me is a much more compelling argument than something that comes from folklore, or the lady next door who swears by it.


The three prime risk factors in Australian cancer rates were identified as obesity, drinking too much alcohol and smoking.

Smoking caused one in five cancer deaths, while regularly drinking too much alcohol boosted the risk of several cancers including breast and bowel.

Staying within a healthy body weight range was found to be more important than following particular nutritional guidelines.

These results challenged widespread belief in the power of juices and vegetable-based “anti-cancer” diets to avoid or fight various types of the disease.

This means a slim person who doesn’t eat enough fruit and vegetables would probably have a lower risk of developing cancer than someone who is overweight but eats the recommended daily amount of fruit and five colored vegetables.

There was also no convincing evidence on how Australians could modify their diet to reduce the risk of cancer.

The most important thing about diet is limiting energy (kilojoule) intake so people don’t become overweight or obese, because this has emerged as a risk factor for a number of cancers, including breast, prostate, bowel and endometrial (uterus).

The link between eating red meat and bowel cancer was “weak” and the Cancer Council supported guidelines advising people to eat red meat three or four times a week. (There used to be a wonderful bumper bar sticker in Australia which went “You’re in cattle country – eat beef ya bastards!”)

Likewise, a high intake of fat, considered a prime culprit since the 1970s, was found to have only a “modest” link to breast cancer.

The risk of every type of cancer is increased by obesity. Experts predicted a surge in cancer as a result of Australia’s obesity epidemic, but say exercise can play a vital role in cutting cancer rates, potentially halving the risk of some cancers.

Surprisingly, fiber was deemed to have no significant benefit in avoiding bowel cancer – although calcium was associated with a 20 per cent reduced risk.

Now, I know that several parties will want to take me to task over this, but I’ll stick with the evidence, rather than the well educated guesses.

Obesity and smoking are the prime culprits. Neither requires expensive treatments. Dieting is free, just the same as stopping smoking. And forget the five colors.