High Vitamin C Levels in Blood Are Found Beneficial
High levels of vitamin C in the blood reduce the risk of death from all conditions, according to a new British study.
Individuals with the highest levels of vitamin C in their blood had only about half the risk of death within a specific time period as those with the lowest levels, Dr. Kay-Tee Khaw and his colleagues at University of Cambridge School of Clinical Medicine report in the March 3 Lancet (https://www.thelancet.com).
Khaw and his associates studied 19,496 men and women, ages 45 to 79, living in Norfolk in eastern England. Participants completed a health and lifestyle survey, underwent a physical examination and had levels of vitamin C in their blood measured. They were then followed for four years.
The team concluded that an increase in blood vitamin C levels associated with eating an extra 50 grams of fruit or vegetables every day, the equivalent of an apple or orange, produced a 20% decrease in the risk of death. The vitamin reduced the risk of death from cardiovascular disease, heart attacks and, for men, cancer--as well as the overall risk of death within the time period.
The team studied only vitamin C from fruits and vegetables, not supplements. Japanese researchers reported in October that high blood levels of vitamin C are associated with a lower risk of stroke.
Soy Can Bolster Levels of ‘Good’ Cholesterol
Adding soy to the diet can increase levels of high-density lipoproteins, the so-called good cholesterol, even for people who already have normal cholesterol levels, according to researchers from Tulane University.
Dr. Jiang He and associates studied 60 men and 90 women, ages 35 to 65, all of whom had normal cholesterol levels. Half ate cookies containing soy protein supplements every day; the rest ate cookies containing a carbohydrate placebo. They reported last week at an American Heart Assn. meeting in San Antonio that, after 12 weeks, the people receiving the soy supplements had a 4.7% increase in high-density lipoprotein compared with the control group.
Asthma Increases Heart Risk for Nonsmokers
Asthma increases the risk of contracting heart disease among nonsmokers by about a third and being treated for asthma increases the risk by 82%, Oakland researchers reported at the San Antonio heart meeting. Previous studies have shown that asthma increases heart disease among mixed groups of smokers and nonsmokers, but the new study is the first to document it among nonsmokers.
Dr. Carlos Iribarren and his colleagues at Kaiser Permanente’s Division of Research studied 22,036 patients between the ages of 35 and 89 to reach their conclusion. It is not clear, they said, whether asthma treatment itself increases the risk of heart disease or whether it is simply a marker for a more serious form of asthma. But they recommended that physicians treating patients for asthma keep a closer watch on other potential risk factors for heart disease, such as hypertension and cholesterol levels.
Fatty Fish Give Seniors a Healthy Heart Boost
Eating fatty fish such as tuna, salmon and mackerel can reduce the risk of heart attack among the elderly, according to another report at the heart association meeting. Fish are thought to be valuable in the diet because they contain omega-3 polyunsaturated fatty acids, which protect the heart through a mechanism that is not yet completely understood.
Dr. David S. Siscovick and his colleagues at the University of Washington looked at 4,000 men and women older than 65 in a study that has been ongoing since 1988. They found that those who ate at least one serving of fatty fish per week had a 44% lower risk of dying from a heart attack. Those who ate lean fish such as cod, catfish and snapper, however, had no reduced risk.
Meth Use, Long-Term Brain Damage Linked
Methamphetamine use causes long-term damage to the brain, slowing motor functions and reducing thinking ability, according to two new studies from Brookhaven National Laboratory in Upton, N.Y.
In one, Dr. Nora Volkow and her colleagues used PET (positron emission tomography) scans to measure brain function in 15 former heavy methamphetamine users and 18 healthy people. They reported in the March issue of the American Journal of Psychiatry (https://ajp.psychiatryonline.org) that the former users had significantly lower levels of key chemicals called dopamine transporters in crucial areas of the brain, even a year or more after their last drug use. Neuropsychological tests also showed worse motor and cognitive functions among the former users than among the healthy controls.
In a second study in the same journal, they examined the brain’s use of sugar--a measure of brain activity--in the subjects. They observed greater metabolic activity in the brains of the former users, an indication that their brains were inflamed.
“This is objective evidence that methamphetamine is damaging to the brain,” Volkow said. “These changes are much greater than what we have seen with heroin, alcohol or cocaine.”
An Inaccurate Screen for Down’s Syndrome
Using ultrasound to detect Down’s syndrome in the second trimester of pregnancy is not an accurate screening measure, even though it is widely used in the United States, according to UC San Francisco researchers. Positive results from the tests frequently expose women to unnecessary amniocentesis procedures, which subjects the fetuses to higher risk, they said.
Dr. Rebecca Smith-Bindman and her colleagues examined 56 articles covering ultrasound screening for Down’s syndrome. In addition to obvious structural abnormalities, such screening usually looks for one of seven markers that are thought to be associated with Down’s syndrome, including a thickening of the back of the neck, small cysts in the fetal brain and a higher level of fluid in the kidneys. About 10% to 14% of fetuses will display one of these markers, they report in the Feb. 28 issue of the Journal of the American Medical Assn. (https://jama.ama-assn.org), but only 1% actually have Down’s syndrome.
With the possible exception of the thickening of the back of the neck, they concluded, none of the markers is a reliable indicator of Down’s syndrome. But ultrasound studies that reveal structural abnormalities, such as heart defects, are a good indicator of the disorder, they said.
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Medical writer Thomas H. Maugh II can be reached at thomas.maugh@latimes.com. Capsules runs every Monday.
