Antioxidants

Definition

There are several families of antioxidants. The antioxidants generally found in vegetables belong to the carotenoid family, which are plant pigments. In most cases they give the vegetable its colour. These include:

• ß-carotene and lycopene, which belong to the subfamily of carotenes;
• Lutein, zeaxanthin and ß-cryptoxanthin, from the subfamily of xanthophylls.

The best known is beta-carotene, which is a precursor of Vitamin A (it's also known as "pro-Vitamin A"): after being modified in the body, a unit of ß-carotene can produce Vitamin A. Beta-cryptoxanthin is also a Vitamin A precursor. Other molecules act as antioxidants as well and can be present in fruits and vegetables: polyphenols, Vitamins A, E and C and certain minerals and trace elements (selenium, copper, zinc, manganese).

Role in the body

• Antioxidant activity: fights oxidative stress and free radicals (molecules responsible for aging and certain diseases).
• Precursor of Vitamin A: for ß-carotene and ß-cryptoxanthin
• Other roles: The antioxidants cited here play many different roles within the body. Moreover, their antioxidant action is sometimes not their primary role.

Sources in vegetables and other foods (Source: Ciqual)  

Foods with the highest content of beta-carotene	µg/100g
Raw carrot	10,000
Dandelion, parsley	7,000-8,000
Dried apricot, cooked spinach, lamb's lettuce, Hokkaido squash, chard, sweet potato	4,000-5,000
Red pepper, mango, cress, sorrel	2,000-4,000
Melon, apricot, liver	1,000-2,000
Purslane, cress, tomato, butter, peach, pumpkin	500-1,000

Vegetables with the highest content of lycopene: canned or jarred tomato sauce (15,151 µg/100g), raw tomato (2,573 µg/100g), raw red pepper (308 µg/100g) Vegetables with the highest content of lutein + zeaxanthin: Cooked spinach (11,308 µg/100g), cooked turnip (8,440 µg/100g), canned peas (1,350 µg/100g), cooked Brussels sprouts (1,290 µg/100g), raw lettuce (1,223 µg/100g), cooked broccoli (1,080 µg/100g), canned pumpkin (1,014 µg/100g) Vegetables with the highest content of ß–cryptoxanthin: Cooked red pepper (2,071 µg/100g), cooked pumpkin (1,450 µg/100g), raw red pepper (490 µg/100g), cooked carrot (202 µg/100g)

Recommended intake

The RDA (Recommended Daily Amount) of beta-carotene is 4.8 mg/day (or 4,800 µg/day). There are no official recommendations regarding intake of the other antioxidants. There are no RNAs (Recommended Nutritional Allowances) by age bracket for the French public. However, it is commonly recommended that about 60% of Vitamin A intake come from carotenoids (alpha-, beta-carotene and beta-cryptoxanthin), but the distribution among these carotenoids is not given.

Deficiency / Excess

Carotenoid intake among the French public is estimated at 5 mg/day, primarily from vegetables. Inadequate intake of antioxidants would exacerbate the effects of oxidative stress (aging, risk of disease). Some segments of the population have an inadequate antioxidant intake and/or are subject to greater oxidative stress, including menopausal women, the elderly, the obese and smokers.

Disadvantages

Some antioxidants are sensitive to oxidation and light but fairly stable in heat.

Tips / advice from the nutritionist

Vary the colours of the fruits and vegetables you eat. They'll provide you with the antioxidants you need for good health! Bear in mind that some antioxidants, such as the lycopene in tomatoes, are better absorbed when combined with a little fat. The lycopene in tomatoes and the carotenoids in carrots are absorbed more effectively when the tomatoes or carrots are cooked in a little oil. Is that why Mediterranean food is so often rich in vegetables prepared with olive oil? It has a guaranteed effect on your health!

To learn more

Download the monograph on antioxidants on our "Health Professionals" page.