Basic Science: Mediterranean Diet Boosts Antioxidant Power

Compared to the low-fat American Heart Association diet, the traditional Mediterranean diet rich in olive oil has more capacity to counteract potentially harmful “free radicals” and “reactive oxygen species” in our bodies, according to researchers at the University of Navarra in Spain.

Our tissues normally contain free radicals and reactive oxygen species, which are intrinsic to cell metabolism.  They serve useful purposes.  In excessive amounts, however, many believe they cause “oxidative damage” and thereby contribute to chronic degenerative conditions such as atherosclerosis, aging, dementia, and cancer.

Antioxidants are thought to neutralize free radicals and reactive oxygen species, which may lead to better health.

The PREDIMED study is an ongoing Spanish project testing the heart-protective effects of the Mediterranean diet in high-risk people over the course of four years.  The three intervention groups are 1) Medi diet plus supplemental virgin olive oil, 2) Medi diet plus extra tree nuts, and 3) low-fat American Heart Association diet.

After three years of follow-up, the researchers measured “total antioxidant capacity” in the bloodstream of a subset of the PREDIMED participants.

They found that the two Mediterranean diet groups had significantly greater total antioxidant capacity, about 50% more than the low-fat control group.  Within the Medi + olive oil group, the participants with the highest levels of antioxidant capacity actually tended to lose weight, an association not seen in the other groups.

The Researchers’ Conclusions

Mediterranean diet, especially rich in virgin olive oil, is associatied with higher levels of plasma antioxidant capactiy.  Plasma total antioxidant capacity is related to a reduction in body weight after three years of intervention in a high cardiovascular risk population with a Mediterranean-style diet rich in virgin olive oil.

In other words, the Mediterranean diet with virgin olive oil may help you keep your weight under control, and the antioxidant capacity may contribute to the well-documented health benefits of the diet.

Steve Parker, M.D.

PS:  It’s impossible to tell from this report just how much weight loss was seen in the high-TAC Medi+olive oil subjects.  I doubt it was much.  Baseline body mass index for all participants was around 29, so they were overweight and just a shade under obese.

PPS:  Both the Ketogenic Mediterranean and Diabetic Mediterranean Diets mandate minimal amounts of olive oil consumption, with no upper limit.

Reference: Razquin, C., et al. A 3 year follow-up of a Mediterranean diet rich in virgin olive oil is associated with high plasma antioxidant capacity and reduced body weight gain.  European Journal of Clinical Nutrition, 63 (2009): 1,387-1,393.  doi 10.1038/ejcn.2009.106


Filed under Fat in Diet, Health Benefits, Mediterranean Diet, Weight Loss

4 responses to “Basic Science: Mediterranean Diet Boosts Antioxidant Power

  1. Was the diet higher in olive oil than usual? And did the group with nuts then limit the amount of olive oil to keep fat amounts similar?

  2. Emily Deans

    Do you know if they were cooking with the olive oil, or if they primarily ate the olive oil cold, as a dressing or dip?

  3. Steve Parker, M.D.

    Unfortunately, I’ve misplaced my copy of the article and it’s not free online.

    My recollection is that the oil-supplemented participants were given free olive oil (1 liter/wk for family use?) and instructions on how to use it either in cooking or raw/uncooked. Questionnaires documented higher olive oil consumption than in the other two groups, but I don’t recall by how much.

    The Medi diet + nuts group had the “usual” amount of olive oil. They were given free nuts weekly.

    Total fat amounts were not designed to be kept constant. No attempt was made to control total fat or caloric intake, or to alter body weight.

    I’ll report back here if and when I find my article copy!


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