Women consuming too much red meat may have a higher risk of stroke than women eating less, says a new study. Red meat is high in saturated fat and cholesterol; both are risk factors for cardiovascular disease, heart attack, and stroke. The United States Centers for Disease Control and Prevention suggests lowering saturated fat intake and eating more fresh fruits and vegetables to help reduce your risk of stroke. Writing in the journal Stroke, researchers examined nearly 35,000 Swedish women, ages 39 to 73. None of the women had heart disease prior to the start of the study in 1997.
After ten years, results showed 4% of the study participants, 1,680 women, had a stroke. Those consuming the most red meat had the highest risk of stroke. Women in the top tenth of red meat intake, consuming at least 3.6 ounces each day, were 42% more likely to have a stroke, compared to women who ate just under one ounce of red meat daily.
Eating processed meat also increased stroke risk. Women eating 1.5 ounces of processed meat each day were 24% more likely to suffer a cerebral infarction, compared to woman consuming less than half an ounce of processed meat each day. Processed meat was not linked to any other form of stroke. Cerebral infarction is a type of stroke caused by a disturbance in the blood vessels supplying blood to the brain. Other types of stroke involve a rupturing of a blood vessel, called hemorrhagic strokes.
The scientists blame red meat and processed meat’s effect on raising blood pressure for the increased stroke risk. According to the World Health Organization (WHO), every year an estimated 17 million people die due to cardiovascular diseases, most notably stroke and heart attack. The WHO lists physical inactivity and unhealthy diet as the main risk factors for heart disease and major cardiac events.
Eating red meat and processed meats like bacon sharply increased heart disease risk in women, U.S. researchers say.Researchers at Harvard School of Public Health in Boston suggest eating healthier protein-rich foods — such as fish, poultry, low-fat dairy and nuts — instead of red and processed meats, may reduce heart disease risk.
“There are good protein-rich sources that do not involve red meat,” first author Dr. Adam Bernstein says in a statement. “You don't need to have hot dogs, hamburgers, bologna or pastrami, which are all fresh or processed meats.”
The study, published in the journal Circulation: Journal of the American Heart Association, finds women having two servings per day of red meat had a 30 percent higher risk of developing coronary heart disease than those who had half a serving per day.
The risk of heart disease was lowered 30 percent when a daily serving of red meat was replaced by nuts. Another red-meat replacement — fish — lowered cardiac risk 24 percent and poultry reduced heart risk by 19 percent.
Bernstein and colleagues examined medical history and lifestyle — including diet — for 84,136 women, ages 30-55, enrolled the Nurses' Health Study from 1980 to 2006. During the 26-year period, the researchers documented 2,210 non-fatal heart attacks and 952 deaths from coronary heart disease.
The new data come from an ongoing National Institutes of Health-AARP study and involved more than 300,000 participants. Researchers found that those study participants who reported eating the most processed meat had about a 30 percent greater risk of bladder cancer than those who ate the least.
What's more, those whose diets were highest in nitrites and nitrates (from processed meat as well as other sources) were about 33 percent more likely to develop bladder cancer than those whose diets contained the smallest amounts of these compounds.
Bladder cancer is currently the 10th most common cancer in the US, with over 70,000 cases diagnosed each year.
Link to Bladder Cancer Needs Confirmation; Link to Colorectal Cancer Convincing
The evidence that consumption of processed meat is linked to colorectal cancer was judged convincing by the independent expert panel behind the major AICR/WCRF report, Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective.
This same report, published in 2007, found the evidence linking red and processed meat to bladder cancer too sparse to make a judgment. Although this new study's findings need to be confirmed, it represents a major contribution to the scientific literature on diet's role in bladder cancer.
Higginbotham noted that the AICR/WCRF report's findings are continually updated; data from this and other studies will be added to AICR/WCRF's database and are scheduled to be reassessed by independent experts in the future.
Until that time, AICR reiterates that for people who are concerned about cancer, there is already good reason to limit consumption of red meat and avoid processed meat.
Source: American Institute for Cancer Research
Heavy meat-eating could be part of an overall unhealthy diet or unhealthy lifestyle, Vergnaud and her team note.
Because meat is “energy-dense” (meaning it packs more calories by weight than veggies or fruits, for example), it could influence appetite control, they add. However, the researchers did attempt to take overall dietary pattern into account, as well as education, physical activity level, whether or not people smoked, and their total calorie intake.
Based on the findings, a person who cut their meat consumption by 250 grams daily (about a half-pound) could conceivably reduce their 5-year weight gain by around 4 pounds.
While this is a relatively small amount of weight from an individual's point of view, the researchers add, gaining an average of 4 pounds in 5 years “could have an important effect from a population perspective.”
“More importantly,” they add, “our results do not support that a high-protein diet prevents obesity or promotes long-term weight loss, contrary to what has been advocated.”
SOURCE: American Journal of Clinical Nutrition, online June 30, 2010.
The researchers, led by Renata Micha, a research fellow in the department of epidemiology, and HSPH colleagues Dariush Mozaffarian, assistant professor in the department of epidemiology and Sarah Wallace, junior research fellow in the department of epidemiology, systematically reviewed nearly 1,600 studies. Twenty relevant studies were identified, which included a total of 1,218,380 individuals from 10 countries on four continents (United States, Europe, Australia, and Asia).
The researchers defined unprocessed red meat as any unprocessed meat from beef, lamb or pork, excluding poultry. Processed meat was defined as any meat preserved by smoking, curing or salting, or with the addition of chemical preservatives; examples include bacon, salami, sausages, hot dogs or processed deli or luncheon meats. Vegetable or seafood protein sources were not evaluated in these studies.
The results showed that, on average, each 50 gram (1.8 oz) daily serving of processed meat (about 1-2 slices of deli meats or 1 hot dog) was associated with a 42% higher risk of developing heart disease and a 19% higher risk of developing diabetes. In contrast, eating unprocessed red meat was not associated with risk of developing heart disease or diabetes. Too few studies evaluated the relationship between eating meat and risk of stroke to enable the researchers to draw any conclusions.
“Although cause-and-effect cannot be proven by these types of long-term observational studies, all of these studies adjusted for other risk factors, which may have been different between people who were eating more versus less meats,” said Mozaffarian. “Also, the lifestyle factors associated with eating unprocessed red meats and processed meats were similar, but only processed meats were linked to higher risk.”
“When we looked at average nutrients in unprocessed red and processed meats eaten in the United States, we found that they contained similar average amounts of saturated fat and cholesterol. In contrast, processed meats contained, on average, 4 times more sodium and 50% more nitrate preservatives,” said Micha. “This suggests that differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats.”
Dietary sodium (salt) is known to increase blood pressure, a strong risk factor for heart disease. In animal experiments, nitrate preservatives can promote atherosclerosis and reduce glucose tolerance, effects which could increase risk of heart disease and diabetes.
Given the differences in health risks seen with eating processed meats versus unprocessed red meats, these findings suggest that these types of meats should be studied separately in future research for health effects, including cancer, the authors said. For example, higher intake of total meat and processed meat has been associated with higher risk of colorectal cancer, but unprocessed red meat has not been separately evaluated. They also suggest that more research is needed into which factors (especially salt and other preservatives) in meats are most important for health effects.
Current efforts to update the United States government's Dietary Guidelines for Americans, which are often a reference for other countries around the world, make these findings particularly timely, the researchers say. They recommend that dietary and policy efforts should especially focus on reducing intake of processed meat.
“To lower risk of heart attacks and diabetes, people should consider which types of meats they are eating. Processed meats such as bacon, salami, sausages, hot dogs and processed deli meats may be the most important to avoid,” said Micha. “Based on our findings, eating one serving per week or less would be associated with relatively small risk.”
Applying spices to beef not just enhances its taste but can also cut down your risk of cancer, suggests a new study. J. Scott Smith, a Kansas State University food chemistry professor, has pursued different projects in recent years seeking ways to reduce heterocyclic amines (HCAs).
HCAs are the carcinogenic compounds that are produced when muscle foods, such as ground beef patties, are barbecued, grilled, boiled or fried. Consuming HCAs through meat increases risk factors for colorectal, stomach, lung, pancreatic, mammary and prostate cancers.
In a research, Smith found that certain spices containing natural antioxidants would reduce HCA levels by 40 percent when applied to beef patties during cooking.
“Cooked beef tends to develop more HCAs than other kinds of cooked meats such as pork and chicken. Cooked beef patties appear to be the cooked meat with the highest mutagenic activity and may be the most important source of HCAs in the human diet,” Smith said.
Previous studies have shown that meat products cooked below 352 degrees Fahrenheit for less than four minutes had low or undetectable levels of HCAs, with HCAs increasing with higher temperatures and added cooking time. It's not a good idea to lower cooking temperatures too much, so antioxidant spices with phenolic compounds can block HCAs before they form during heating and still allow high temperatures to be maintained.
Smith's research team investigated six spices – cumin, coriander seeds, galangal, fingerroot, rosemary and tumeric – and found that the latter three had the highest levels of antioxidant activity toward inhibiting the formation of HCAs, with rosemary as the most effective.
Consumers can take advantage of the spices by integrating them into their cooking regimen. Previous research in his laboratory has demonstrated that some commercial rosemary extracts, available for purchase on the Internet, can inhibit HCA formation by 61 to 79 percent. Smith's earlier work also showed that Thai spices can inhibit HCA formation by 40 to 43 percent.
Smith said future research in this area will investigate what some marinades or powders can do to inhibit HCAs when applied to a cooked patties. His earlier project showed that marinating steaks with certain herbs, rosemary and other antioxidant spices also reduces HCAs.