Sandra M. Grant P.Dt. - Registered Clinical Nutritionist
My Blog


Antioxidants and disease prevention

Hello everyone and welcome to my blog!

I thought I would start with a topic that I find quite fascinating...antioxidants. We have all been told since we were knee high to a grasshopper to eat our fruits and vegetables, but has anyone ever explained why we need to eat so many? Perhaps you've heard that they're low in calories and will help keep you slim. Maybe it's because their fibre content helps you feel full sooner so you actually eat less. Or perhaps its the fact that they contain a lot of water, and we all know how good water is for us! These are all valid points, but new research is focusing on other compounds they contain called antioxidants. Antioxidants are compounds that may help protect against oxidative damage which in turn can lead to premature aging and disease. 

To understand how they work, we need a little chemistry 101. You might want to get comfortable and prop yourself up with a pillow so you don't bump your head as you nod off, but I'll try to simplify it and keep it short. Oxidative damage can be caused by external factors such as exposure to radiation, cigarette smoke, air pollution or industrial chemicals, but it can also be caused by oxygen. SInce oxygen is vital to life, any effort to avoid it would be futile to say the least. Oxygen is a negatively charged ion and as it travels through the body it tries to neutralize itself by removing ions from cells in the body. This results in formation of what we call "free radicals". Antioxidants can replace the ions taken away by oxygen and prevent the damage. The best way to see this in action is to cut an apple in half, sprinkle only one half of the apple with lemon juice, and leave both halves exposed to the air. In a few minutes the half of the apple without lemon juice will turn brown. This is the effect of the oxygen working on the flesh of the apple. The other half remains white as the vitamin C (a rich antioxidant found in citrus fruit) prevents damage to the fruit. The same thing happens in the body. Fruit and vegetables can protect us from oxydative damage whether it's due to external toxins or simply breathing! Damaged cells result in free radicals and free radicals are associated with pre-mature aging and a number of diseases including atherosclerosis, Alzheimer's disease, cancer, and rheumatoid arthritis.

Two things are important to remember. 

1: Our exposure to free radicals is occurring constantly thoughout the day. Antioxidants only stay in our system for a few hours. Sooooo we need to eat fruit and/or vegetables OFTEN. Ideally we should be having some type of fruit with breakfast and again between meals, as well as LOTS of vegetables at lunch AND supper. 5 to 6 times a day for good protection. 

2. Research does not show the same result with antioxidants in supplement form. It appears to be the synergy of all the compounds together (vitamins, minerals, fiber, antioxidants and other phytochemicals) within the plant that may protect us from premature aging and disease.

Additionally some supplements can be detrimental. For example Beta-carotene supplementation might increase the risk of smoking-related cancers and should be avoided by tobacco users. Rich antioxidant supplements can interfere with some chemotherapy medications and should be avoided during chemo treatment. 

So there you have it. Now you understand why we keep on pushing for more and more plant foods in the diet. They are currently our greatest protection against many diseases. Different plants provide different compounds which work at different levels of disease prevention so variety is important!

I hope you're still awake and have found this as fascinating as I do...but if you don't then I hope at least you've learned something and you'll consider adding a few extra sprigs of broccoli or maybe fresh herbs to dinner tonight. 


Ref: Res Pharm Sci. 2010 Jan-Jun; 5(1): 1–8.,
       R.Beliveau, Ph.D., D. Gingras, Ph.D., Foods that fight Cancer, 2005

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