Effects of a good diet on health

It is generally accepted that an unhealthy lifestyle, which includes having an unbalanced, unvaried diet and a lack of physical exercise increases weight gain (and obesity), cardio-vascular diseases, diabetes, hypertension, osteoporosis and cancer.

Most epidemiological surveys analysing the dietary factors involved in the prevention of several pathologies, have highlighted the important role played by fruits and vegetables.

Protective effect of fruits and vegetables

Brocoli et graines de brocoli

The protective effect of fruits and vegetables on most cancers – those associated with the upper aero digestive tract (oesophagus, oral cavity, larynx, and pharynx), stomach, lungs, colon and rectum, in particular – is very well established.

Indeed, over the past thirty years, several hundreds of studies (observation, intervention and mechanistic studies) have established a relation between eating fruits and/or vegetables and cancer.

In over 80% of them, one or more groups of fruits or vegetables have been found to have a protective effect (source: Programme National Nutrition Santé PNNS).

These studies have also highlighted the protective role of fruits and vegetables in relation to cardio- and cerebro-vascular diseases, diabetes, in the fight against obesity and in the prevention of osteoporosis.

Nutritional prevention of cancer

Cancer is a chronic disease caused by a number of factors, including:

  • Genetics
  • Lifestyle (smoking, diet, exposure to UV rays, etc…)
  • The natural or domestic environment (radioactivity, infections, chemical products, etc…)
  • The professional environment (chemical products, radiation…)

Diet plays an essential role.

A fatty diet increases the risk of cancer. Similarly, overconsumption of dairy products probably also heightens this risk.

But with healthier eating, around one third of the most common cancers could be avoided.

Fruits and vegetables could potentially help reduce the risk of cancer due to a number of components that they contain:


Element Found in…
Fibres Lentils, peas, broad beans, beans – red and white, avocado, strawberries, apples, artichokes, tomatoes…
Polyphenols Broccoli, strawberries, lychees, grapes, apricots, apples, artichokes, parsley, shallots, green tea
Isothiocyanates Broccoli, cabbages

(vitamin A precursor)

carrots, apricots, mangoes, spinach, sweet potatoes, parsley…
Lycopene  Water melons, grapefruits, tomatoes, guava, strawberries
Folates (vitamin B9) Water cress, dandelions, spinach, chicory, lambs lettuce, melons…


Several epidemiological studies have suggested that eating cruciferous vegetables, such as broccoli, seems to correlate with reduced risk of prostate cancer.

More information
  • Rapport « Alimentation, Nutrition, Activité Physique et Prévention du cancer » de l’AICR (American Institut for Cancer Research)
  • PNNS (Programme National Nutrition Santé) : www.mangerbouger.fr
  • Kolonel LN et al. Vegetables, fruits, légumes and prostate cancer : a multiethnic casecontrol study. Cancer epidemiology, biomarkers and prevention. 2000 ; Vol9 : 795-904
  • Kirsh VA and al. Prospective study of fruit and vegetable intake and risk of prostate cancer.J Natl Cancer Inst. 2007; Vol 99(15): 1200-1209
  • Vainio H, Bianchini F, eds. IARC Handbooks of Cancer Prevention, Vol 8: Fruit and Vegetables. Lyon, France: IARC Press, 2003.
  • Steinmetz K. A., Potter J. D. Vegetables, fruit, and cancer prevention: a review. J. Am. Diet. Assoc., 96: 1027-1039, 1996.
  • Block G., Patterson B., Subar A. Fruit, vegetables, and cancer prevention: a review of the epidemiological evidence. Nutr. Cancer, 18: 1-29, 1992.