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It seems that a great debate rages about whether we all need to eat our 5 a day in order to maintain our health or whether it is conceivably cheaper, faster and easier to obtain necessary vitamins and minerals from supplements.

The thrust of my question is... what is the evidence? Are we more inclined to lean on the crutch of saying real foods must be healthier, or this just a symptom humankind's psychological tendency to mistrust manufactured supplements in favour of wholesome foods?

  • Five a day and (un-)processed foods are two completely different concepts. Are you skeptical that we need 5 portions of vegetable and fruit per day, or that organic food is better? I've edited your question assuming the first. – Sklivvz Jan 5 '12 at 14:32
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    No, with the greatest respect, I think you have misread my question entirely. My question is nothing to do with the difference between 5 a day and un-processed food, and entirely nothing to do with "organic" food. I am asking for the evidence and opinion of other members on whether obtaining necessary vitamins and minerals by taking pills containing them has any less merit than eating a varied diet consisting of fruit, vegetables and less processed foods that we are constantly being asked to partake of. – DjDemonD Jan 5 '12 at 14:58
  • I thought that's what I meant!? Do you agree with the edit? :-) – Sklivvz Jan 5 '12 at 15:13
  • I agree with the edit but found the comment about it ambiguous. – DjDemonD Jan 5 '12 at 15:30
  • The results of this study: [Dietary Supplements and Mortality Rate in Older Women][1] need to be accounted for in any argument in favor of multivitamins over food. > In older women, several commonly used dietary vitamin and mineral supplements may be associated with increased total mortality risk; this association is strongest with supplemental iron. I doubt that the corresponding "high iron foods increase risk of death" studies have ever been done, much less can be found online. [1]: archinte.ama-assn.org/cgi/content/short/171/18/1625 – user951 Jan 5 '12 at 15:35
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The recommendation comes from "Food, Nutrition, Physical Activity, And The Prevention Of Cancer: A Global Perspective":

PERSONAL RECOMMENDATIONS

  • Eat at least five portions/servings (at least 400 g or 14 oz) of a variety of non-starchy vegetables and of fruits every day
  • Eat relatively unprocessed cereals (grains) and/or pulses (legumes) with every meal3
  • Limit refined starchy foods
  • People who consume starchy roots or tubers as staples also to ensure intake of sufficient non-starchy vegetables, fruits, and pulses (legumes)

The paper also contains a quick summary of the justification, plus two chapters dedicated to the specific findings:

Justification

An integrated approach to the evidence shows that most diets that are protective against cancer are mainly made up from foods of plant origin.
Higher consumption of several plant foods probably protects against cancers of various sites. What is meant by ‘plant- based’ is diets that give more emphasis to those plant foods that are high in nutrients, high in dietary fibre (and so in non- starch polysaccharides), and low in energy density. Non- starchy vegetables, and fruits, probably protect against some cancers. Being typically low in energy density, they probably also protect against weight gain. Further details of evidence and judgements can be found in Chapters 4 and 8.
Non-starchy vegetables include green, leafy vegetables, broccoli, okra, aubergine (eggplant), and bok choy, but not, for instance, potato, yam, sweet potato, or cassava. Non- starchy roots and tubers include carrots, Jerusalem arti- chokes, celeriac (celery root), swede (rutabaga), and turnips.

So basically the recommendation is to eat plants, not to eat vitamins. Vitamins are not a good substitute for eating a lot of veggies in this sense.

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