Most people would have heard by now that we all should aim to have a daily intake of at least 5 portions of fruits and vegetables and if possible even more. But what is in fruits and vegetables that make the difference in achieving a healthy diet? And why is it not enough to only eat spinach like Popeye? I have conducted my own investigation and have summarised the positive effects upon health surrounding a high diet of fruit and vegetable consumption.

Prehistoric clues

Today’s Western diet is very high in animal protein yet the prehistoric humans followed a diet which was very high in plant sources such as grains and seeds and guess what fruit and vegetables. Many biologists put forward that the diet our apelike ancestors ate is the diet the human body could metabolise best because we are well adapted to digest these sources of energy. Whereas the modern diet which is much higher in animal protein and fats and is far more processed challenges our body systems. The few human generations passed since we were living as nomads are simply not enough to adapt through natural selection and gene mutations to the new energy dense foods offered in every supermarket and restaurant.

Population clues

Nutritionist and health professional have studied the health and diet of large numbers of people around the globe and frequently results are pointing towards diets high in fruit and vegetable as association to lower numbers of chronic diseases. These studies often highlight that people who eat regularly eat a large variety of fruit and vegetables have lower numbers of chronic heart disease, stroke, diabetes and several forms of cancer (e.g. cancer of the stomach, esophagus, lung, oral cavity, pharynx, endometrium, pancreas and the colon).

These studies however cannot be understood as the prove that fruits and vegetables are the reason for the better health of people who regularly eat more fruits and vegetables, because it could be other lifestyle choices which are done more often in people who eat more fruits and vegetables such as higher levels of physical activity or specific substances in fruits and vegetables which could also be found in other foods.

So what is in fruits and vegetables which may provide health promoting effects?

You may wonder what is so special about fruit and vegetables in comparison to the lovely steak from a beef or a pig. Well, plant sources of food are often lower in energy than animal products but do contain large amounts of vitamins, minerals and antioxidants called collectively micronutrients, this makes them particular nutrient dense per gram. Moreover some of the vitamins, minerals and antioxidants are not found in animal products.

Micronutrients are vital for almost all metabolic processes and although we do not need large amounts of vitamins, minerals and antioxidants if any of them is missing the bodily functions can go very bad and even low levels of them are likely to influence the immune systems or the bodies self defense mechanisms. Hence if we would only consume animal sources of food we would not only miss out some of the micronutrients altogether we would also consume a diet which is much higher in energy per gram and as such might lead us to overeat and gain weight.

Besides these micronutrients fruits and vegetables are also an important source of fibre which is cannot be digested by the human body but needs and feeds an active gut micro flora. There are 2 types of fibre soluble and insoluble fibres, both are thought to be beneficial for health.

Soluble fibre helps to release glucose more gradually into the blood stream and as such helps to regulate blood sugar levels and prevents of type 2 diabetes. Furthermore soluble fibre binds fat and cholesterol and acts therefore preventive for heart disease. Insoluble fibre helps to make you feel full, to prevent constipation and to clean your gastro intestinal tract.

Micronutrient losses are high in fruits and vegetables

Cooking foods changes not only their appearance and taste but also their nutrient composition, some of the micronutrients become more available whereas others are being lost. Additionally storage of foods will always lead to at least some level of degeneration of the food and nutrient losses, which are usually high in fruit and vegetables. What is more, micronutrients supplied by animal products often have a higher bioavailability which means they are easier absorbed by the human body, which is down to the much more similar chemical structure of animal foods to the human  physique. Hence one may wonder whether fruit and vegetables after all really give you more micronutrients per gram than any animal products. This is why scientists have studied the levels of different micronutrients in large numbers of people while assessing the fruit and vegetable content in their diet, these investigations found that levels of several micronutrients in the human body are usually higher in people who eat more fruit and vegetables.

Fruits and vegetables vs. complex supplements

So it seems the vitamins, minerals, antioxidants and fibres in fruits and vegetables make them so powerful, hence theoretically these micronutrients and fibres if supplied by supplements should convey the same effects to humans who are not eating enough fruit and vegetables. Yet the regulations concerning supplement production and sales are currently not strict enough to prevent claims being made on  products which contain lower amounts of micronutrients or different combinations of these micronutrients, this means such supplements would be unable to mimic the specific effects fruits and vegetables have in the human body.

Additionally many micronutrients interact with each other in ways which may prevent the absorption of one another or influence the active pathways of each other in the body. Such micronutrient interactions are common therefore current suggestions are to stay away from large single micronutrient supplements as effects of such intakes may severely reduce the availability of other micronutrients.  Complex supplements on the other hand claim to have the ‘right’ mixture of micronutrients to prevent such negative interactions, yet as mentioned a large proportion of supplements on the market has not the qualities advertised hence aiming to eat 5 a day, will not only be cheaper but potentially also safer to get your micronutrients.

A final note – consuming these supplements increases surely the CO2 emissions compared to getting your micronutrients from fresh fruits and vegetables as the production often uses large amounts of energy and in some cases where the supplements are coming from natural sources fruits and vegetables might be the original source.

Andrea Zick, Esteem Fitness Nutritionist London

Esteem Fitness – Personal Training London and the South East