Phytochemicals, bioactive plant nutrients, might help prevent overweight and obesity

Vegetables and fruits contain abundant amounts of phytochemicals (bioflavonoids), bioactive plant nutrients, which are thought to be vital to the body for many reasons and linked to a reduced risk of all kinds of conditions from heart disease and cancer to dementia and bone loss.  The recommendations to eat plenty of these plant-based foods are certainly valid and very important.  A high intake of phytochemical compounds has been shown to be important for optimal health and prevention of disease.

A recent study (1) has linked high intakes of phytochemicals with reduced adiposity,fat tissue, as well as reduced oxidative stress, a kind of stress that occurs in the cells of our bodies when they are under attack by molecules known as ‘free radicals’.  In the body antioxidant defences are important to prevent damage by these free radical molecules which can cause inflammation and are linked to many diseases.  Many phytochemicals act as antioxidants in the body.

The authors of this study(1) used a simple ‘phytochemical index’ to determine the levels of these plant chemicals consumed by 54 people aged between 18-30 years.  Participants were ordered into normal weight and overweight groups.  Dietary records and blood samples were collected. The phytochemical index was a way of comparing the number of calories consumed from plant-based foods with the overall number of daily calories. 

The adults in the two groups consumed about the same amount of calories.  However overweight-obese adults consumed fewer plant-based foods and subsequently fewer protective trace minerals and phytochemicals and more saturated fats. They also had higher levels of oxidative stress and inflammation than their normal-weight peers, these processes are related to the onset of obesity, heart disease, diabetes and joint disease.  The authors conclude that having more phytochemicals in the diet is related to a lower fat mass and lower levels of oxidative stress.  Phytochemicals may be having an effect on the metabolic processes associated with obesity but further research would be necessary to elucidate this (1)

As mentioned earlier, phytochemicals are found in large amounts in vegetables and fruits, they are also present in nuts, beans, pulses and lentils.  These are foods that we are always being reminded to include in high levels in the diet.  In a press release (2) the author of the study stated  “We need to find a way to encourage people to pull back on fat and eat more foods rich in micronutrients and trace minerals from fruits, vegetables, whole grains and soy,”.  The author goes on to recommend (2)Fill your plate with colorful, low-calorie, varied-texture foods derived from plants first. By slowly eating phytochemical-rich foods such as salads with olive oil or fresh-cut fruits before the actual meal, you will likely reduce the overall portion size, fat content and energy intake. In this way, you’re ensuring that you get the variety of protective, disease-fighting phytochemicals you need and controlling caloric intake.”

Plant based foods are generally lower in calories but more filling than processed foods since they contain plentiful amounts of fibre that can help us to feel fuller for longer, these foods really should represent the cornerstone of a healthy diet.  Supplements can never replace a healthy diet, however if you feel you are frequently falling short of eating enough vegetables and fruits you may want to consider taking a bioflavonoid supplement or a food-state multivitamin and mineral supplement to cover any short-term shortfalls.

There are many simple ways to include more vegetables and fruits in the diet e.g.
*Replace processed snack bars with a piece of fruit or a handful of mixed unsalted nuts
*Vegetable sticks with some hummus make a great snack
*Grate an apple into your morning oats/porridge or added a chopped banana – avoid sweet, processed breakfast cereals
*Include plenty of salad in your lunchtime sandwich, 
*Have 2-3 portions of vegetables with your evening meal
*Eat fruit with natural yoghurt as a dessert
*Replace pre-packaged, processed foods as often as possible with fresh produce – the authors of the study state (2)We always want to encourage people to go back to the whole sources of food, the non-processed foods if we can help it,” “That would be the bottom line for anyone, regardless of age and body size, keep going back to the purer plant-based foods. Remember to eat the good quality food first.”

(1)Vincent HK et al.  2009.  Relationship of the dietary phytochemical index to weight gain, oxidative stress and inflammation in overweight young adults. Journal of Human Nutrition and Dietetics.  Sep 4. [Epub ahead of print]
(2)University of Florida (2009, October 22). Phytochemicals In Plant-based Foods Could Help Battle Obesity, Disease. ScienceDaily. Retrieved October 23, 2009, from¬ /releases/2009/10/091021144251.htm

Written by Ani Kowal