Linda F. Benedict, Roy, Heli J.
Research has shown that including fruits and vegetables in the diet is important for the maintenance of health and prevention of disease. Fruits and vegetables have many nutrients such as vitamins C and A and fiber. They also contain non-nutritive antioxidants called phytochemicals, which help reduce the risk of chronic diseases such as heart disease, diabetes, obesity, cancer and neurodegenerative diseases. Antioxidants are involved in the prevention of free-radical-induced damage to the DNA, eliminating free radicals and inf luencing enzyme actions in the cells and organs. These are the events that cause aging and damage to blood vessel walls and inter- nal organs and can then lead to chronic diseases.
One group of phytochemicals called anthocyanins in berries and fruits give these foods a range of colors from red to blue; other phytochemicals give fruits, vegetables and spices their green, yellow, orange or white color. In addition to providing color to berries, fruits and vegetables, they are also strong antioxidants. They reduce small blood vessel permeability and increase their strength, reduce platelet aggregation and improve collagen function. Other phytochemicals eliminate harmful compounds from the body to protect us against cancer and organ damage. Some have similar actions to hormones in our body, while others reduce inflammation. Recent data indicate that some phytochemicals may even help in the fight against obesity and diabetes.
One of the hallmarks of a disease state is when small capillaries allow substances to move in and out of the blood vessels easily. This causes protein molecules to move in spaces where they should not be and draw water with them, resulting in swelling and negative cellular changes. Berry anthocyanins strengthen the small blood vessel walls to make them stronger and tighter so that large protein molecules cannot move out into intercellular spaces.
Platelets are a special type of blood cells that circulate in the bloodstream. They are involved in blood clotting. When there is a wound, they help form clots, so we don’t bleed to death. Excessive aggregation of platelets is one of the causes of heart attacks and strokes; another one is an injury to the internal wall of the blood vessels. Excessively sticky platelets can form clots inside blood vessels, and these clots can get caught in tiny blood vessels in the heart and the brain. Anthocyanins in berries can help reduce platelet stickiness and keep them flowing and reduce the chances of a heart attack or stroke.
Because cancer is a slow-developing disease, diet over time can play a role in its prevention. Several different phytochemicals in many fruits, vegetables, spices, coffee, tea and cocoa kill cancerous cells in the body or disrupt cancer cell growth and development. These phytochemicals influence the enzyme system in the cell and either delay or prevent the cancer from growing and developing. Berries, fruits and vegetables have been shown to help in the prevention of neurodegenerative diseases such as Alzheimer’s and Parkinson’s and agerelated decline in brain functioning. Nerve cells are covered in a layer of fat to protect them from damage, but the fat itself can get oxidized from lack of antioxidants in the diet. Phytochemicals are strong antioxidants and can remove harmful oxidants that could damage the fat layer or the nerve cells themselves. Some of the phytochemicals can enter the brain as well to protect it from oxidative damage. Regular consumption of berries has been found to result in reduced decline in age-related decline in brain functioning.
Diabetes is increasing worldwide as obesity increases. Type 2 diabetes occurs because of pancreatic beta cell damage. However, phytochemicals can offer protection against oxidative damage and protect the beta cells. Not only do they protect the beta cells themselves, they also increase the intake of blood sugar by the muscle cells and prevent an excess release of sugar from the liver to the bloodstream, thereby preventing abnormally high blood sugar levels.
For obesity to develop in an individual, the fat cells must become fully saturated with fat and new fat cells made. The fat cells then increasingly take in fat and expand as a person’s weight increases. New research indicates that phytochemicals from plants prevent the new fat cell from developing and maturing, thereby limiting the number of fat cells a person forms and the amount of fat an individual can accumulate. The existing fat cells, however, have an almost endless limit to holding onto fat.
Phytochemicals from fruits and vegetables are powerful antioxidants that prevent free-radical-induced damage to our cells and organs and, thereby, delay aging related chronic diseases. Including a variety of fruits and vegetables in the diet can delay and prevent the development of cardiovascular disease, diabetes, cancer, hypertension and heart disease.
Heli Roy is an associate professor in the School of Nutrition and Food Sciences and outreach coordinator at Pennington Biomedical Research Center.
(This article was published in the fall 2013 issue of Louisiana Agriculture magazine.)