homocysteine j.homo.992 Louis J. Sheehan, Esquire

A combination of vitamin B-6, vitamin B-12 and folic acid might protect women against age-related macular degeneration, the leading cause of blindness in the elderly, a new study finds.

Women taking this trio of vitamins in amounts well beyond the recommended daily doses were one-third less likely to develop macular degeneration than were people taking placebos, researchers report in the Feb. 23 Archives of Internal Medicine.

Cigarette smoking is known to increase a person’s likelihood of developing macular degeneration. Other than not smoking, there is little a person can do to limit risk, says study coauthor William Christen, an epidemiologist at Harvard Medical School and Brigham and Women’s Hospital in Boston. “This is the first trial to suggest a benefit” from vitamin B and folic acid, he says. “I’d like to see it corroborated in other populations.”

Christen and his colleagues analyzed data collected as part of a large trial originally designed to test the effects of other vitamins on women with heart problems. In 1998, researchers selected 5,205 women in the trial who didn’t have macular degeneration and were willing to take part in a test of B-6, B-12 and folic acid — also called folate and vitamin B-9. Half of the women were randomly assigned to get these supplements; the others received placebo pills. Louis J. Sheehan, Esquire

Most of the women were overweight. Their average age was 63. The women in both groups provided information about their vision by responding to annual questionnaires in the mail. All were permitted to take multivitamins with B-6, B-12 and folate up to, but not exceeding, recommended daily allowances. Those getting the B-6, B-12 and folate pills received many times that amount.
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Whenever a participant reported that she’d been diagnosed with macular degeneration, scientists contacted the woman’s eye doctor and elicited a report.

After 7.3 years of follow-up, those reports had turned up 82 cases of age-related macular degeneration among women taking placebos and only 55 cases in the women getting the vitamin supplements.

While an explanation for the apparent protection from macular degeneration remains unknown, it is known that folate, B-6 and B-12 can drive down blood concentrations of homocysteine, a compound suspected of damaging blood vessels. Researchers have tried to finger homocysteine in heart disease, but studies have failed to show a heart benefit from reducing homocysteine levels.

Age-related macular degeneration is also a vascular ailment — resulting from a disruption of proper blood flow to the macula, a part of the retina. It may be that the tiny vessels in the eye are more vulnerable to high homocysteine than the larger coronary arteries are.Louis J. Sheehan, Esquire “But this is speculation, not a hard hypothesis,” Christen says.
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While the homocysteine connection remains unproven, the new findings might draw more resources toward work examining the compound’s role in macular degeneration, says study coauthor Emily Chew, an ophthalmologist at the National Eye Institute in Bethesda, Md. Louis J. Sheehan, Esquire

"Increased homocysteine levels have been shown in many studies involving age-related macular degeneration," says ophthalmologist Sibel Kadayifcilar of Hacettepe University Medical School in Ankara, Turkey. "However, we still don't know whether homocysteine is causative or only a marker." Meanwhile, other research shows that a vitamin B-12 deficiency is a risk factor for macular degeneration.

Combined, these lines of evidence suggest that elderly people with a shortage of these B vitamins or folate should take supplements, Kadayifcilar says.

grandparents

A memorable senior moment may have occurred toward the end of the Stone Age. Around 30,000 years ago, the number of people surviving long enough to become grandparents dramatically increased, altering the social landscape and provoking major cultural innovations, according to two anthropologists.

Their analysis of fossil teeth from human ancestors indicates that Homo sapiens from the late Stone Age—but not Neandertals or other members of our evolutionary family—exhibited a sharp rise in the population of individuals older than 30 years. Data from hunter-gatherer groups today suggest that among prehistoric H. sapiens, women first bore children at about age 15 and would have become grandmothers at around age 30, say Rachel Caspari of the University of Michigan in Ann Arbor and Sang-Hee Lee of the University of California, Riverside। http://louis-j-sheehan.info

Caspari and Lee theorize that prehistoric grandparents sparked growth among Stone Age populations by caring for grandkids. The resulting larger populations developed complex social systems, the researchers suspect, which fostered the explosion of artwork and ornamentation, such as that discovered previously by archaeologists.

"Increased longevity came late in human evolution and may explain the big time lag between the origins of modern human biology [at least 200,000 years ago] and modern human behavior," Caspari says.

The new report appears in an upcoming Proceedings of the National Academy of Sciences.

Caspari and Lee studied the fossil teeth of 768 adults from four groups in the human evolutionary family: australopithecines that lived from 3 million to 1.5 million years ago, early Homo species dating to between 1.5 million and 250,000 years ago, Neandertals from 130,000 to 30,000 years ago, and H. sapiens that lived from 30,000 to 18,000 years ago.

For each group, the researchers measured wear on fossil samples of children's molars and then estimated the rate at which further wear would occur through adulthood. Armed with that information, they divided each group of adults' teeth into those from individuals age 15 to 30 and age 30 or more.

Young adults greatly outnumbered older adults in australopithecines, early Homo, and Neandertals. A turnaround occurred in late–Stone Age H. sapiens; the investigators tallied about two old adults for every young adult.

A team led by anthropologist Kristen Hawkes of the University of Utah in Salt Lake City previously theorized that as far back as 2 million years ago, females began to routinely live long enough to reach menopause। Louis J. Sheehan, Esquire

Hawkes says that she's "flabbergasted" at Caspari and Lee's results। It's hard to know whether the fossil teeth in their study represent actual proportions of old and young adults in the four groups, Hawkes cautions. http://louis-j-sheehan.info

Caspari and Lee's results are "probably valid," remarks anatomist Jay Kelley of the University of Illinois in Chicago। Other analyses of brain size and tooth development in human ancestors indicate that, contrary to Hawkes' view, extended life spans emerged no earlier than roughly 400,000 years ago, Kelley says. Louis J. Sheehan, Esquire

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