Do all dietary fats increase body weight? The Olive oil case

Is it paradoxical that olive oil intake does not increase body weight? It seems so, as olive oil is an energy-dense food, frequently consumed in south European countries. These countries have increasingly high obesity prevalence, according to different international organizations, including the World Health Organization. Actually, in 2008 the New York Times published that the Mediterranean Diet had succumbed to fast food.

However, recent evidences are pointing out in the opposite direction, indicating that olive oil could be helpful against body weight gain. A cross-sectional study on 6,352 Spanish adults, published early this year, showed that olive oil intake did not affect body mass index (BMI) and the risk of obesity after adjustment for total energy intake.


Alright, but this is a cross-sectional study. ¿What happens if olive oil is administrated to a group of human subjects? The strongest evidence we have to date is the results of the PREDIMED study. This is a three-arm randomized trial aimed to assess the effects of Mediterranean Diet in primary cardiovascular prevention in more than 7000 individuals at high cardiovascular risk. A substudy of the PREDIMED trial showed that increased adherence to the Mediterranean Diet, with 1L per week of olive oil, was inversely associated with diabetes incidence, which occurred in the absence of significant changes in body weight or physical activity.

It has been even suggested that olive oil intake, as part of a Mediterranean Diet, is inversely associated with BMI and obesity in adults and children. Therefore, it might not be the excess of fat from olive oil intake what is causing the epidemic of obesity in Southern Europe, but as the New York Times suggested, but the retreat of the traditional diet of the region.

Obesity facilitates tumor growth in mice redardless of their diet

Epidemiologic studies have strongly associated the incidence of cancer with obesity, but their pathophysiologic connections remain obscure. Researchers at the Institute of Molecular Medicine at the University of Texas Health Science Center at Houston may have discovered a new explanation as to why obese patients with cancer often have a poorer prognosis compared with those who are lean.

Mikhail G. Kolonin and his colleagues evaluated how adipose stromal cells (ASC), transplanted  into mice, can serve as perivascular adipocyte progenitors that promote tumor growth. Their initial results confirmed this hypothesis: In obese and lean mice that ate the same diet, tumors grew much faster in obese mice than they did in lean mice. They also found that ASC were expanded into the circulation in obesity and that they traffic from endogenous adipose tissue to tumors in several mouse models of cancer.

Once in the tumors, some of these cells developed into fat cells, while others were incorporated into tumor-associated blood vessels, which support tumor growth by bringing in oxygen and nutrients to cancer cells. According to the researchers, this ability of ASC is likely one of the main reasons that the excess of these cells in tumors was associated with increased malignant cell proliferation.


Source: Cancer Research