Garlic Counteracts Age-Related Artery Stiffening

[Guest guest]

New Technique Shows Drug Effects in the Human Brain

 

Researchers at the Brain Imaging Center of McLean Hospital in

Belmont, Massachusetts, have published the first research study

showing the cocaine-induced changes in the blood vessels within the

human brain.

 

Cocaine-induced strokes are rare but increasing, and are presumed to

be caused by a drug-induced spasm in the vessels nourishing the

brain. Many researchers have studied drug effects by administering

drugs to animals and then dissecting the animals' brains.

 

The McLean team used a technique called magnetic resonance

angiography to study the brain blood vessels in 24 healthy men in

their 20s and 30s who reported a history of occasional cocaine use.

The researchers administered a single low dose of cocaine

intravenously and observed brain function 20 minutes later.

 

The researchers found that, indeed, even low-dose cocaine constricts

brain blood vessels, sometimes severely, supporting concerns that it

can cause either acute or gradual loss of brain cells.

 

Kaufman MJ, Levin JM, Ross MH, et al. Cocaine-induced cerebral

vasoconstriction detected in humans with magnetic resonance

angiography. JAMA 1998;279:376-80.

 

 

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Yet Another Saccharin Report: Rat Tests Don't Apply

 

Saccharin packets carry warnings about possible cancer risk based on

rat experiments. But after three decades, tests of saccharin on

animals have clearly shown only one thing: the tests can't be

trusted.

 

The Journal of the National Cancer Institute of January 7, 1998,

reported results of long-term saccharin tests on monkeys and used

the opportunity to raise fundamental questions about the value of

animal safety tests.

 

Mice do not get cancer from eating saccharin. Neither do hamsters,

guinea pigs, or, for that matter, monkeys, according to the latest

series of tedious long-term tests. Monkeys fed saccharin in baby

bottles as infants and mixed with bread as adults in tests lasting

from 6 to 25 years showed no cancer risk. An accompanying editorial,

however, criticized the study's choice of dosages, species, and

numbers, and reminded readers of the need for reducing, refining,

and replacing animal tests.

 

None of these tests has been able to trump human epidemiologic

studies, which show none of the effects seen in rats.

 

Male rats fed saccharin apparently develop bladder cancers because

of a chain of events that does not occur in humans. When rats ingest

large amounts of any sodium salt—sodium saccharin, sodium ascorbate,

or others—a calcium phosphate-containing precipitate forms in their

urine. This only happens when there is a pH over 6.5 and a large

concentration of protein, calcium, and phosphate in the urine. Rats

have 100 to 1,000 times greater protein concentration in their

urine, compared to humans, and a much more concentrated urine,

ranging from 1,000 to 3,000 mOsm/L, compared to 100 to 500 for

humans.

 

Animal tests have not proven whether the largely superfluous

artificial sweetener is safe or not, but they have clearly shown

that the tests themselves are undependable. They are also expensive.

A single test of one product in one rodent species takes several

years and costs well over one million dollars.

 

Takayama S, Sieber SM, Adamson RH, et al. Long-term feeding of

sodium saccharin to nonhuman primates: implications for urinary

tract cancer. J Natl Cancer Inst 1998;90:19-25.

Zurlo J, Squire RA. Is saccharin safe? Animal testing revisited. J

Natl Cancer Inst 1998;90:2-3.

 

 

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CANCER

 

A Drink May Be Good for Your Heart,

But Raises Cancer Risk

 

Those having a drink or two a day in hopes of protecting their heart

may find the remedy too good to be true. It has long been known that

even one drink a day substantially increases a woman's risk of

breast cancer, and new evidence presents similar concerns about

colon cancer.

 

Several epidemiologic studies have shown that alcohol (especially

beer) consumption increases the risk of colon and rectal cancer. A

new study of patients with a history of colon polyps, which are

often harbingers of colon cancer, found that having seven or more

drinks per week doubles the risk of recurrence.

 

Alcohol may do its dirty work by interfering with folic acid, a B-

vitamin that helps repair damaged DNA. Alcohol, like smoking,

reduces the amount of folic acid in the blood and blocks its

biological actions.

 

IGF-1 and Prostate Cancer

 

Excessive levels of a natural com-pound in the blood, called insulin-

like growth factor-1 (IGF-1), are linked to greater risk of prostate

cancer. IGF-1's natural function is to encourage cells to multiply.

However, it also promotes aggressive cancer cell growth. It is

already known to encourage breast cancer cell growth and is an even

stronger cancer promoter than estrogen. A new study shows that men

who have the highest levels of IGF-1 in their bloodstream have more

than four times the risk of prostate cancer, compared to those with

the lowest levels. Researchers are now considering using IGF-1

measurements in combination with prostate-specific antigen (PSA) to

more precisely estimate cancer risk.

 

IGF-1 is produced in the liver and other tissues. It is also found

in cow's milk, which, after all, is designed by nature to foster

rapid growth in a baby calf.

 

Milk has IGF-1 levels ranging from 6 to 162 ng/ml, depending on

whether it comes from a pregnant or postpartum dairy cow.

 

IGF-1 may be the reason that several studies have linked milk

consumption to cancer of the breast, prostate, and kidney.

 

Stress Lowers Immune Defenses against Cancer

 

Cancer patients are understandably stressed by their diagnosis and

the rigors of treatment. A new study of a group of women undergoing

treatment for breast cancer found that stress weakens their natural

anticancer defenses. The participants filled out questionnaires that

assessed their stress levels. At the same time, researchers drew

blood samples and measured the ability of specialized white blood

cells, called natural killer cells, to eliminate cancer cells. They

found that the more stress the women had, the worse their ability to

destroy cancer cells and the more unresponsive their immune systems

were in general.

 

The good news is that stress-reduction training can strengthen

immunity. Teaching progressive muscle relaxation to healthy adults

in a retirement home boosted their natural killer cell activity by

30 percent.

 

Diet and exercise help, too. Vegetarians have double the natural

killer cell activity compared to omnivores, and a new review of 16

research studies shows that regular exercise cuts both pre- and

postmenopausal breast cancer risk by 12 to 60 percent. How much

exercise do you need? Most studies that have found benefits favor

vigorous exercise roughly three to four hours per week.

 

Chan JM, Stampfer MJ, Giovannucci E, et al. Plasma insulin-like

growth factor-1 and prostate cancer risk: a prospective study.

Science 1998;279:563-5.

Baron JA, Sandler RS, Haile RW, et al. Folate intake, alcohol

consumption, cigarette smoking, and risk of colorectal adenomas. J

Natl Cancer Inst 1998;90:57-62.

World Cancer Research Fund/American Institute for Cancer Research.

Food, Nutrition, and the Prevention of Cancer: a Global Perspective.

Washington, D.C., 1997, pp. 460-2.

Andersen BL, Farrar WB, Golden-Kreutz D, et al. Stress and immune

responses after surgical treatment for regional breast cancer. J

Natl Cancer Inst 1998;90:30-6.

Gammon MD, John EM, Britton JA. Recreational and occupational

physical activities and risk of breast cancer. J Natl Cancer Inst

1998;90:100-17.

 

 

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HEART DISEASE

 

Artery Damage from Cigarettes May Be Permanent

 

Cigarette smoking promotes the growth of artery blockages and

increases heart attack risk. Unfortunately, quitting may not

entirely eliminate the adverse effects of smoking.

 

The Atherosclerosis Risk in Community (ARIC) study measured carotid

(neck) artery blockages by ultrasound in 10,914 people in Minnesota,

Maryland, Mississippi, and North Carolina. Repeat measurements three

years later showed that those not exposed to tobacco smoke had the

least growth in their artery blockages, 25.9 mm over the three-year

period. Smokers were much worse off. Their blockages had grown by

43.0 mm. Exposure to passive smoking added an extra 6 mm of artery

blockage growth, both for nonsmokers and past smokers. Those who had

smoked previously but quit were still growing blockages at a rate

faster than for never-smokers, with a 32.8 mm growth of their artery

blockages.

 

Smokers with hypertension or diabetes had a much more pronounced

effect of smoking, with blockage growth of 58.0 mm and 80.1 mm,

respectively.

 

Bottom line: Quitting helps, but your arteries may never be the same.

 

Garlic Counteracts Age-Related Artery Stiffening

 

As we get older, the body's main artery, the aorta, gradually loses

its elasticity, becoming unable to expand with each pulse of blood.

As the aorta stiffens, each pulse from the heart squeezes straight

through the narrowed passage at high speed, stressing the arterial

system.

 

Garlic may help preserve the aorta's natural resilience. Dr.

Harisios Boudoulas of Ohio State University collaborated with

researchers in Mainz, Germany, in a study of people who took garlic

powder supplements daily for two years. " The aortas of our 70-year-

old subjects who took garlic were as elastic as the aortas of 55-

year-old subjects who didn't take garlic. " Overall, 300 mg of garlic

each day reduced aorta stiffening by 15 percent.

 

Howard G, Wagenknecht LE, Burke GL, et al. Cigarette smoking and

progression of atherosclerosis: the Atherosclerosis Risk in

Communities (ARIC) study. JAMA 1998;279:119-24.

Breithaupt-Grogler K, Ling M, Boudoulas H, Belz GG. Protective

effect of chronic garlic intake on elastic properties of aorta in

the elderly. Circulation 1997;96:2649-55.

http://www.pcrm.org/magazine/GM98SpringSummer/GM98SpSm10.html