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Free Radicals and Antioxidants–Facts You May Not Know

I hope you all had a great 4th of July holiday!

Today my post is about free radicals and antioxidants–some facts I learned during my classes last semester in my MS program. Whether the post brings out new info, busts a misconception, or re-enforces something you already new, I hope you will find it beneficial in some way. I’m going to put them in bullets so they will be easier to follow.

Free radicals are oxygen-containing compounds that attack healthy cells and cause their damage. It’s thought that free radicals cause cancers, while antioxidants fight them. Antioxidant vitamins and minerals are vitamin C, vitamin E, beta-carotene, and selenium.

  • While antioxidants slow down the growth of cancers in lab animals, clinical studies are a different story

For example, vitamin E did not prevent cancer in women over the age of 45, selenium and vitamin E supplements did not prevent prostate cancer in men, and vitamin C or vitamin E supplements did not reduce the risk of prostate or any type of cancer in middle aged or older men.

  • In some cases, anti-oxidant supplements can cause more damage than benefit

This is the case of beta-carotene and smoking. Smoking causes damage, so antioxidants would help offset it. How could that hurt? Well, smokers who took beta-carotene supplements increased their risk of developing lung cancer than smokers who didn’t.

  • Some free radicals in your body are beneficial

This was a difficult concept to digest and accept, but it’s true. Exercise increases the formation of free radicals, so you would think you need to ensure your body has some antioxidants to prevent damage. Not always. Exercise also improves insulin resistance which helps lower blood glucose level for people with diabetes. One study found that taking vitamin E and C supplements after exercise prevented the beneficial effect of exercise on diabetes. The authors concluded that somehow, free radicals have an important role in this case.

The other time free radicals are generated for a good reason is when white blood cells fight infections. I will not go into details of the biochemistry of it, but the immune system needs to form some free radicals from oxygen to kill bacteria, fungi, and other particles. If you want to read more about this, research “respiratory burst.”

I have three more points to make about free radicals and antioxidants, but I’m worried it will be too long of a post. I will save them for Wednesday.

Have a great day!

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Comments on this entry are closed.

  • Reeni July 5, 2010, 7:33 pm

    Hope you had a great 4th too! Thanks for all the great information! I always learn something useful when I come here.

  • Stella July 6, 2010, 9:40 am

    Hey Nour, I haven’t visited you for a while. I hope your’e doing well! Salam…
    You know, as someone who studies nutrition from a natural and holistic stand point, I just don’t take studies involving extracts or isolated vitamins too seriously. The vitamin isn’t at work with all of the other nutrients in whole foods, so I just question the validity of their results. Plus, that beta carotene study showed that supplement form beta carotene worsened the overall situation for people with certain cancers where as whole food beta carotene (carrots, sweet potatoes, turmetic, etc) did indeed ‘seem’ to better the situation. Plus, researchers are always stating one thing and then, you know, two years down the road taking it back and saying they were mistaken…
    I don’t know. Obviously, I’m a bit passionate about this topic though, as I just wrote a novel here (smile).
    Thanks for tweaking my brain this morning, Nour! Stella

  • Nour El-Zibdeh, RD July 7, 2010, 9:02 am

    Reeni: Thank you for the comment. It makes me happy to know you learned something new–that makes up my day 🙂

    Stella: I agree with you 100%. I hope you get a chance to read my post today and it will confirm what you said.

  • Nadine July 9, 2010, 11:40 am

    Maybe that is why people who have always exercised their whole lives and are in shape seem to look older in the face than people who are overweight and sedentary. It may be all of the free radicals they are producing. Even though they are much healthier, the free radicals are aging their skin.

    • Nour El-Zibdeh, RD July 9, 2010, 1:12 pm

      Hi Nadine,
      Well, looking “older” depends on many things. For example, genes make a difference; African American and Asians don’t seem to look as old as their white counterparts. Also, smoking, stress, quality of diet, sun exposure, skin care, etc.. so I won’t blame it all on exercise. Someone who works out every day for extended hours for several years may seem to look older, but at the level most people exercise at–an hour a day if they are able to–has more benefit than harm. It’s important to weigh the benefit vs the risk of exercising, and so far, exercise helps with weight management, preventing heart disease, diabetes, and cancers, it helps alleviate depression and improve mood, and important for bone health as well. So I can’t see free-radical production as a good reason to not exercise, especially that this amount of free radical production may be beneficial to begin with. Plus, when the body ages, it ages from the inside and out. We still need to exercise, and take care of our skin by staying hydrated, eating a healthy diet, and applying sunblock if you exercise outdoors.

  • Stace November 24, 2010, 12:09 am

    To Nadine I’d say it is probably the diet of those that tend to work out. I found they eat one high in (animal) based proteins, which puts a lot of stress on the body’s digestive system and kidneys. If a cleaner diet is followed, I’m sure they would look a younger.
    As well, fat plumps up a face more and makes it less defined, that is why heavy people may look younger. However, being overweight and sedentary with a less than ideal diet produces free radicals on its own.

    • Nour El-Zibdeh, RD November 24, 2010, 10:24 pm

      Thank you Stacy for stopping by and leaving us a comment. I think it’s unfair to generalize how the diets of those who work out look like. Yes, some serious athletes–think of football players–tend to eat a lot of high calorie, processed, fast-foods, but that’s not all football players and certainly not all athletes. I know some people who work out and have the healthiest diets, and many follow vegetarian diets too.

      Our digestive system and kidneys are able to handle animal based protein. I personally believe than animal products can fit in a healthy diet in moderation and there are many clean animal foods—grass-fed beef for example. I agree with you though, that regardless of what you think of animal foods, we all need to eat more plants. I prefer to focus on eating more plant foods than eating less animal foods.

      And yes, having excess fat, especially abdominal fat, increases inflammation in the body and produces free-radicals.