A journal of running, healthy food, mountains, bikes and technology by Julia Revitt

Free radicals are cells that can damage other cells and cause cancer, aging, heart disease and have been linked to other diseases such as Parkinson’s and Alzheimer’s. They also play an important biological role in the body including cell death and controlling bacteria in cells.

Free radicals can be formed by the following;

  • Smoking
  • Pollution
  • Pesticides
  • Eating burnt meat
  • Eating fried foods
  • Strenuous exercise

The body has 2 layers of defense when it comes to free radicals, enzymes and antioxidants.


Deactivating enzymes are the 1st layer and it is important to eat nutrients that support these enzymes. There are 4 different enzymes which have different functions in deactivating free radicals. They are;

  • Superoxide dismutase
  • Catalase
  • Glutathione peroxidase
  • Glutathione reductase

The deactivating enzymes need copper, manganese, selenium. There appears to be an adaptive effect from regular exercise that increases the amount of these minerals in the body as opposed to non-exercisers. It therefore follows that sports people should take care to make sure they eat plenty of foods containing these minerals (as they need more than sedentary people). Eating 5 or more fruits and vegetables each day and taking a good multi-vitamin & mineral supplement should ensure adequate intake. To increase the intake of these enzyme beneficial nutrients, the minerals can also be found in the following foods;


  • Liver
  • Oysters
  • Seaweed
  • Shiitake mushrooms
  • Sesame seeds
  • Soy products


  • Wheat
  • Brown rice
  • Hazelnuts
  • Pine nuts
  • Mussels
  • Rice cakes
  • Oat bran


  • Brazil nuts
  • Kidneys
  • Oysters
  • Turkey
  • Chicken
  • Eggs
  • Salmon



Antioxidants are the body’s 2nd level of defense against free radical damage. They work by converting the damaged cell into something much less reactive. The antioxidants are;

  • Vitamin A (betacarotene)
  • Vitamin C
  • Vitamin E
  • Polyphenols

As athletes it is very important that we limit our free radical damage by eating plenty of foods containing these nutrients. Free radical damage after strenuous exercise includes muscle soreness that can reduce muscle strength for up to 10 days and it also compromises the muscle’s ability to store glycogen (it’s fuel). As mentioned before, make sure you eat 5 or more different fruits and vegetables each day and boost your intake with a good multi-vitamin & mineral supplement. The vitamin content of food is greatly reduced with cooking – try to eat as many of your fruits and vegetables raw or lightly cooked if necessary. Do not fry when at all possible as this destroys the antioxidant properties of foods.

The following foods are some of the best sources of these antioxidants;

Vitamin A (betacarotene)

  • Carrots
  • Red peppers
  • Sweet potatoes
  • Tomatoes
  • Kale
  • Spinach
  • Pumpkins

Vitamin C

  • Oranges
  • Raisins
  • Cauliflower
  • Red cabbage
  • Broccoli
  • Berries
  • Guava
  • Kiwi fruit
  • Lemons

Vitamin E

  • Nuts & peanut butter
  • Sunflower oil & seeds
  • Broccoli
  • Asparagus
  • Avocado
  • Wheat germ
  • Peas
  • Beans


Polyphenols are healthy substances found in plants. Excellent source include;

  • Green tea
  • Red wine
  • Onions
  • Olive oil
  • Nuts

So to get the best protection against free radical damage, eat plenty of the foods listed above, in addition;

  • Eat 5 different fruits and vegetables every day. Have a different selection each day and try to pick a broad range of colours to get the maximum amount of different nutrients.
  • Take a good quality multi-vitamin and mineral supplement.
  • Don’t smoke and try to stay out of smoky atmospheres.
  • Limit your time spent in traffic and polluted areas.
  • Avoid any burnt foods.
  • Eat organic foods.
  • Eat raw fruit and vegetables whenever possible.
  • Limit consumption of fried food.




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