Medical News Monthly: Mediterranean Diet

Showing posts with label Mediterranean Diet. Show all posts

Sunday, January 1, 2017

Friday, January 1, 2016

Sunday, October 4, 2015

Mediterranean Diet may Reduce Breast Cancer Risk - The PREDIMED Trial

A paper by Toledo et al published in JAMAInternal Medicine suggests that women could reduce their breast cancer risk by following a version of the Mediterranean diet that goes heavy on extra virgin olive oil.

The study was conducted within the frame of PREDIMED trial a 1:1:1 randomized, single-blind, controlled field trial from 2003 to 2009, on 4282 women aged 60 to 80 years who were at high cardiovascular disease risk.

Participants were randomly allocated to a Mediterranean diet (MeDiet) that was supplemented with extra-virgin olive oil (EVOO), a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat).

After a median follow-up of 4.8 years, they identified 35 confirmed cases of breast cancer. The observed rates (per 1000 person-years) were 1.1 for the Mediterranean diet with extra-virgin olive oil group, 1.8 for the Mediterranean diet with nuts group, and 2.9 for the control group. The multivariable-adjusted hazard ratios versus the control group were 0.32 (95% CI, 0.13-0.79) for the Mediterranean diet with extra-virgin olive oil group and 0.59 (95% CI, 0.26-1.35) for the Mediterranean diet with nuts group. When both MeDiet groups were merged together, they observed a 51% relative risk reduction (95% CI, 0.25-0.94). When they excluded women who were diagnosed with breast cancer during the first year after enrollment, the results remained unchanged. The information that was collected in this study was on invasive breast cancers only therefore noninvasive tumors such as DCIS, in situ cancers, were not included or analyzed in this trial.

The data from the PREDIMED trial, suggest a significant inverse association between consumption of a MeDiet supplemented with EVOO and breast cancer incidence. A high consumption of EVOO (≥15% of total energy intake) seems to be instrumental in obtaining this significant protection. A non-significant risk reduction was observed with the MeDiet supplemented with nuts.

In a different trial, the Lyon Diet Heart Study, which was also a randomized trial, a protective effect of a Mediterranean-type diet against overall cancer incidence was observed, supporting the hypothesis of an anticancer effect of the MeDiet.

The low rate of breast cancer among women in the PREDIMED trial should not be surprising. If the MeDiet is actually protective against breast cancer, a low incidence is to be expected in a study with these characteristics, especially when overall adherence to such diet was good already at baseline.

Several biological mechanisms could explain the anti-carcinogenic properties of EVOO. All types of olive oil provide a high supply of monounsaturated fatty acids, mainly oleic acid, as well as squalene, but EVOO also contains additional biologically active compounds as polyphenols.

These compounds are known to have a likely role in breast cancer prevention due to inhibition of tumor growth and proliferation, migration, and invasiveness of breast cancer cells in both in vitro or in vivo breast cancer models. Olive oil has been associated with increased apoptosis of cultured breast cancer cells. It has also been reported to reduce intracellular reactive oxygen processes and to prevent oxidative DNA damage in both human breast epithelial cells and human breast cancer cells.

The authors conclude that the findings of their trial suggest a beneficial effect of the Mediterranean diet supplemented with extra-virgin olive oil as a primary prevention of breast cancer. The authors also state that their findings need to be confirmed with longer-term and larger studies, as breast cancer in addition to being the most prevalent cancer in women worldwide, with 1.7 million new cases diagnosed in 2012 while its incidence is has increased by 20% due to growth and aging of the population.

JAMA Intern Med. published online September 14, 2015.

Wednesday, July 2, 2014

The Mediterranean Diet

The Mediterranean diet is derived from the traditional diets of Greece, southern Italy and Spain. Its uniqueness relates to the use of olive oil instead of butter and the daily consumption of nuts, legumes, fruits and vegetables. People in the Mediterranean countries depending on their local (island, valleys or mountains) eat moderate amount of fish, or meat such as poultry and/or dairy products (mostly as cheese and yogurt). They also drink a low amount of wine and/or spirits. According to the American Heart Association, there's no one "Mediterranean" diet but a dietary pattern that includes the above-mentioned foodstuff and the use of olive oil a monounsaturated fat that does not raise blood cholesterol.

The incidence of heart disease and death rates in Mediterranean countries is lower than in the United States. Although diet appears to have a role, other factors such as genetic, lifestyle, physical activity and extended social and family support systems may also play a part.

Before advising people to adhere to a strict Mediterranean diet, well designed and controlled studies are needed to determine whether the diet itself or other factors (genes, lifestyle, social) account for the lower deaths from cardiovascular disease among humans. The findings from the following two studies are supportive of the beneficial effect the Mediterranean diet and the consumption of nuts has in our health.

An important multi-center study that was conducted in Spain was published in the New EnglandJournal of Medicine. The authors evaluated the effect of the Mediterranean diet in the prevention of cardiovascular disease in individuals who were at high risk for cardiovascular events, but with no apparent cardiovascular disease. A total of 7447 persons were enrolled whose age ranged from 55 to 80 years; with a male to female ratio 43 to 57 percent were randomly assigned, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (advice to reduce dietary fat). The end point was the rate of major cardiovascular events such as myocardial infarction, stroke, or death from cardiovascular causes. A primary end-point event occurred in 288 participants. The group assigned to a Mediterranean diet with extra-virgin olive oil experienced 96 events while and the group assigned to a Mediterranean diet with nuts experienced 83 events, respectively, versus 109 events in the control group. On the basis of these results, the trial was stopped after a median follow-up of 4.8 years as the authors concluded that among persons at high cardiovascular risk, a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events.

According to a study from the USA that was also published in the New England Journal of Medicine, people who ate a daily handful of nuts were less likely to die from any cause over a 30-year period and were more slender than those who didn’t consume nuts. For their research, the authors analyzed information from the Nurses’ Health Study that provided data on 76,464 women, and the Health Professionals’ Follow-Up Study that provided data on 42,498 men. The researchers report a 29% reduction in deaths from heart disease and an 11% reduction in death rate from cancer. It appeared that the protective effect was similar to all types of nuts. Those who ate nuts less than once a week had a 7 percent reduction in mortality; once a week, 11 percent reduction; two to four times per week, 13 percent reduction; five to six times per week, 15 percent reduction; and seven or more times a week, a 20 percent reduction in death rate.

Based on this and other smaller studies, the U.S. Food and Drug Administration concluded that eating 1½ ounce per day of most nuts “may reduce the risk of heart disease.”

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