Health News

MEAT AND POTATOES MAN? – men who eat more red meat (mostly beef and pork), processed meat (bacon, sausage, cold cuts, ham, and hot dogs), and grilled or barbecued meat have a higher risk of advanced prostate cancer.

Researchers at the National Cancer Institute tracked over 175,000 men aged 50 to 71 in the NIH-AARP Diet and Health Study for nine years. The risk of advanced prostate cancer was 30 percent higher in those who reported eating the most red meat (about 5 ounces a day) than in those who ate the least (less than one ounce). The risk was also 30 percent higher in those who ate the most processed meat (about 2 ounces a day) than in those who ate the least.

Finally, the risk was also about 30 percent higher in those who consumed the most iron from meat, the most benzo[a]pyrene (found in grilled or barbecued meat), or the most nitrites (which are added to processed meats).

Eat as little red meat and processed meats as possible. Other studies suggest that consuming these foods also raises the risk of heart disease and diabetes. Nutrition action Healthletter 12/09.

GET EMERGENCY HELP FOR STROKE SYMPTOMS – even if the symptoms only last a few minutes. Symptoms lasting less than 24 hours usually indicate that a person has had a mini-stroke, also called a transient ischemic attack, or TIA. About one in eight strokes is preceded by a TIA, according to a Canadian study in Neurology. Other studies have found that most strokes occurring after a TIA can be prevented by drug treatment. The main stroke or TIA symptoms are sudden numbness or weakness of the face, one arm, or one leg; sudden confusion or trouble speaking or understanding speech; sudden trouble seeing in one or both eyes; sudden trouble walking, dizziness, or loss of coordination; sudden severe headache with no known cause. University of California Berkeley Wellness Letter 12/09.

THE MANY BENEFITS OF EXERCISE:

EXERCISE & CANCER RISK

Regular physical activity is central to reducing cancer risk by indirectly helping to keep off excess weight or in the case of colon cancer, by directly reducing the cancer risk. Studies show that even light to moderate regular activity is associated with lower risk compared with inactivity.

Researchers at Washington University School of Medicine in St. Louis reviewed 52 studies of exercise and colon cancer and found that the most active people were about 21 percent less likely to be diagnosed than the least active counterparts.

In contrast, it may take more than brisk walking or other moderate activity to lower the risk of breast cancer. With colon cancer, just not being sedentary reduces the risk of the disease whereas with breast cancer, the evidence indicates that the reduced risk occurs only with greater, moderate-to-vigorous activity.

It is never too late to reap the benefits of exercise for cancer risk reduction. Researchers tracked some 119,000 women in their 50s and 60s for seven years in the NIH-AARP Diet and Health Study. Those who reported more than an hour a day of moderate-to-vigorous activity – even if they had not exercised earlier in their lives – were 16 percent less likely to be diagnosed with breast cancer than those who rarely did moderate-to vigorous exercise.

It appears that women who are more aerobically fit are less likely to die of breast cancer according to the NIH studies.

Exercise may also indirectly prevent cancer by keeping the pounds off. The direct effects of exercise are most clearly shown on the risk of large bowel and breast cancer. However, the indirect effect of consistent exercise on cancer risk is that of preventing weight gain.

Weight gain is associated with quite a few cancers, notably post menopausal breast cancer, colorectal cancer, endometrial cancer, pancreatic cancer, and adenocarcinoma of the lower esophagus. There is also accumulating evidence that obesity is a risk factor for several of the blood-forming cancers like leukemia and lymphoma. This is why the American Cancer Society now recommends at least 30 minutes of moderate-to-vigorous physical activity at least five days a week, but that 45 to 60 minutes is preferable.

EXERCISE CREATES NEW BRAIN CELLS

Older adults on average perform slower and less accurately on cognitive tests. However, older individuals who are more fit perform better to the point where they are performing at the same levels as much younger adults.

One explanation may be that consistent exercisers may have increased blood flow to the brain and stimulated growth of new brain cells, new connections or synapses between cells, and new capillaries to distribute the blood and its nutrients. A 2006 study by the University of Illinois had test subjects aged 60 to 79, who were healthy but sedentary, engage in an aerobic exercise training program. After six months, their brain volume had increased. That meant more brain cells and more connections between them. Brain volume did not increase in 30 similar people who participated in a toning and stretching program.

Aerobic exercise increases the supply of a protein called brain-derived neurotrophic factor, or BDNF, which protects brain neurons and promotes the growth of new nerve cells and synapse that are related to learning and memory.

Exercise also appears to boost executive function, which is the ability to plan or make decisions, correct errors, or react to new situations.

EXERCISE BOOSTS INSULIN SENSITIVITY

Insulin is a hormone that allows blood sugar to enter the body’s cells, where it is stored or used as fuel. As we age or when we put on weight, bodies do not respond as well to insulin and can become insensitive, or resistant to the hormone. Insulin resistance increases the risk of heart disease and, if blood sugar levels keep rising, type 2 diabetes.

There are many studies showing that when people do aerobic exercise training, their insulin sensitivity improves within a very short time. Strength training is also very beneficial and can improve insulin sensitivity by 20 percent within a matter of months.

Both aerobic exercise and strength training increase the number of proteins called glucose transporters – particularly GLUT4 – which move glucose from the blood into muscle and fat cells. The more GLUT4 you have, the better your cells respond to insulin.

ANTI-AGING

A study published in Circulation suggested that vigorous exercise may partially reverse aging inside the cells, at the genetic level. In middle-aged long-time runners, there was less shortening of the telomeres (protective caps on the ends of DNA strands), compared to their sedentary counterparts. Such telomere shortening is a sign of aging in cells – like a biological clock. The telomeres of these runners appeared nearly as “young” as those of runners in their twenties. These were elite runners, but scientists speculate that any vigorous, maybe even moderate, exercise done over the long term may help keep genes young.

MINIMIZING VISCERAL FAT GAIN

Everyone gains visceral fat as we age unless we do something about it.

Visceral fat, which accumulates around the organs deep inside the belly, is linked to insulin resistance, heart disease, and diabetes. Subcutaneous fat, which lies closer to the skin, is not as harmful.

A study in 2005 showed sedentary overweight men and women who followed an exercise program equivalent to a brisk 30-minute walk six times a week for eight months stopped gaining visceral fat. If they did more exercise, the equivalent of jogging 20 miles a week, they actually lost 7 percent of their abdominal fat.

Many studies have shown that aerobic exercise will reduce visceral fat as long as you do it consistently. Dieting can also help you lose visceral fat but most of this reverts back to normal within a year because people quit dieting and go back to what they were doing

THE RISK OF BEING SEDENTARY

People who sit for the majority of their day have much higher mortality rates than people who don’t, even if they are physically active during another part of the day.

The health risk of sitting for long periods cannot be minimized by occasional leisure time physical activity. When sitting for long periods, muscles seem to be extremely inactive, which may change the way they metabolize compounds and may affect the regulation of insulin and glucose. Just getting people to stand up changes the physiology in their limbs, which encourages blood flow and increases muscle activity in the lower limbs. (Besides exercising regularly when not on duty, moving around on long flights, standing up when able, and stretching in the seat can aid blood flow and minimize the risk of sitting for long periods of time. – LK)

YOU ARE NEVER TOO OLD TO START

Dozens of studies have documented that you can build up muscles and increase strength with resistance or weight training no matter how old you are.

Resistance training increases muscle strength and volume. Testing on elderly patients showed that exercising three times a week for nine weeks increased muscle volume by 12 percent and strength by 28 percent.

Women test subjects increased their muscle mass only about half as much as men, but their strength gains were equal to the male subjects. Nutrition Action Healthletter 12/09, University of California Berkeley Wellness Letter 4/10.