Fatty food might cause brain damage, say scientists

Fatty foods may damage the region of the brain responsible for regulating a person’s appetite, which could account for why overweight people often find it difficult to stick to a diet, scientists said.

A study has found that a diet rich in saturated fats leads to the sort of damage to the brain’s hypothalamus that would normally be seen during ischaemic stroke, when the nerves are starved of oxygen.

The hypothalamus is a key region of the brain involved in controlling appetite so the findings suggests that saturated fats may be having a direct affect on the ability of the body to stick to a diet, said Lynda Williams of the Rowett Institute for Nutrition and Health at Aberdeen University.

“The hypothalamus is a small area at the base of the brain containing neurones that control the amount of food we eat and the energy we expend. However, this control breaks down in obesity - the system appears not to work - and we don’t really know why this happens,” Dr Williams said.

“To help answer the question we used a strain of mice that is susceptible to weight gain and put half of them on a high-fat diet and the other half on a normal low-fat diet,” Dr Williams said

“After just three days we saw changes to the proteins [of the hypothalamus] and after one week we saw changes to the genes,” she told the British Science Festival.

“Our experiment reveals a potential mechanism whereby a high-fat diet that is energy dense can damage or injure the hypothalamus. These changes may lead to the break down of the energy-balance centres in the brain, and so encourage weight gain and obesity,” she said.

“I’m almost sure it’s a direct effect of the fats on the brain. One of the first things that happens to the hypothalamus early on in high-fat feeding is that it become insensitive to [appetite hormones], so there is a sort of global loss of control of appetite,” she added.

Although the research was carried out on mice, Dr Williams believes the same processes take place in the human brain. “There is some evidence from the US where they did brain scans on obese people and found some indication of damage in the hypothalamus,” she said.

Red Meat tied to stroke risk

By Todd Neale, Senior Staff Writer, MedPage Today

Eating red meat -- including beef, pork, lamb, ham, hot dogs, sausage, and bacon -- may increase the risk of stroke, a meta-analysis showed.

Each one-serving-per-day increase in fresh, processed, and total red meat intake was associated with an 11% to 13% relative increase in the risk of all strokes, driven by an increase in the risk of ischemic stroke, according to Joanna Kaluza, PhD, of the Warsaw University of Life Sciences in Poland, and colleagues.

There was, however, no relationship between red meat consumption and hemorrhagic stroke risk, the researchers reported online inStroke: Journal of the American Heart Association.

The findings are "of great public health importance because of the widespread consumption of red meat and the high morbidity and mortality associated with stroke," Kaluza and colleagues wrote.

Chowing down on red meat has been associated with greater risks of some cancers, coronary heart disease, and diabetes, as well as all-cause mortality and death from cardiovascular disease and cancer.

Studies examining the relationship between red meat and the risk of stroke have yielded mixed results, so Kaluza and colleagues performed a meta-analysis of prospective studies examining the issue.

They identified five publications that included results from six studies (two in Sweden, three in the U.S., and one in Japan) that reported relative risks of stroke with various levels of consumption of red meat -- including pork, often advertised as "the other white meat."

The studies included a total of 329,495 participants and 10,630 cases of stroke.

All of the studies statistically adjusted for age, body mass index, and alcohol consumption, and most further accounted for smoking, physical activity, diabetes, hypertension, energy intake, and fruit and vegetable consumption.

After adjustment, the serving-per-day increase in red meat consumption associated with an increase in the risk of stroke was consistent for fresh meat (RR 1.11, 95% CI 1.03 to 1.20), processed meat (RR 1.13, 95% CI 1.03 to 1.24), and all red meat combined (RR 1.11, 95% CI 1.06 to 1.16).

Among the four studies that had information on stroke subtypes, the risk of ischemic stroke was significantly related to one-serving-per-day increases in fresh meat (RR 1.13, 95% CI 1.00 to 1.27), processed meat (RR 1.15, 95% CI 1.06 to 1.24), and all red meat combined (RR 1.12, 95% CI 1.05 to 1.19).

The researchers suggested a few possible mechanisms to explain the findings, including consumption of high levels of saturated fats, which could lead to a greater risk of stroke from higher levels of total cholesterol, LDL cholesterol, and triglycerides.

Red meat also contains heme iron, and "high doses of iron may lead to oxidative stress, a state with increased peroxidation of lipids, protein modification, and DNA damage," the authors wrote. "If continued for a long time, oxidative stress induced by iron may lead to the development of many diseases, such as cardiovascular disease, type 2 diabetes, atherosclerosis, neurological disorders, and chronic inflammation."

Processed red meat contains sodium and nitrite preservatives, which may also influence the risk of cardiovascular disease, diabetes, and other diseases, according to the researchers.

They acknowledged some limitations of the meta-analysis, possible residual confounding from unmeasured factors in the individual studies, the use of self-report information on red meat consumption, between-study variations in the definition of a serving size and in meat consumption patterns, and possible publication bias.