Vitamin B6:

A Surprisingly Simple Way to Help Prevent Colon Cancer

By Greg Arnold, DC, CSCS, June 24, 2005, abstracted from “Plasma vitamin B6 and the risk of colorectal cancer and adenoma in women�?in the May 2005 issue of the Journal of the National Cancer Institute

Colon cancer is the fourth most common cancer (after lung, prostate, and breast cancers) and the second most common cause of cancer death (after lung cancer).(1) Studies published in medical literature on the ability of increased fiber intake to help prevent colon cancer have differing conclusions. One study(2) found those with the highest intake of fiber (36 grams per day) had the lowest incidence of colon cancer,(3) while another study found “no direct evidence�?in fiber’s ability to prevent colon cancer.

Now, a new study(4) has introduced another supplement that may act as a possible preventive for colon cancer. That supplement is vitamin B6.

In the study, researchers analyzed blood samples from nearly 33,000 women who participated in the Nurses' Health Study in 1989, when they were 30 and 55 years. The researchers proceeded to study blood levels of pyridoxal 5'-phosphate (PLP), the primary active form of vitamin B6 in blood. They divided the patients into four groups from the lowest to the high blood levels of PLP in an effort to determine whether PLP had an effect on these conditions.

The study showed that 194 women developed colorectal cancer and 410 women developed colon polyps. The highest quartile group, those who consumed 8.6 mg per day of vitamin B6, showed a 44 percent lower risk of colorectal cancer and colorectal polyps and a 58 percent lower risk of colon cancer and colon polyps. These results led the researchers to conclude that “vitamin B6 may be inversely associated with risk of colorectal [cancer].�?/FONT>

Folate, Folic Acid, a B vitamin

No Fooling

Folate, a B vitamin found in foods and also known as folic acid (the synthetic form used in supplements and fortified foods), has just earned another gold star. A study that evaluated the dietary habits of 150,000 women over an eight-year period showed that folic acid reduced their risk of developing high blood pressure.

The research, part of the ongoing Harvard Nurses' Health Study, evaluated women in two age groups -- ages 43 to 70... and ages 23 to 44. Women in the younger group who consumed at least 1,000 micrograms (mcg) per day of folic acid in food and supplements had a 46% lower risk for hypertension (high blood pressure) compared with women whose daily intake was less than 200 mcg. In the older group, the risk was 18% lower. Women in both groups who consumed less than 200 mcg of folic acid in food per day but managed to increase the level to at least 800 mcg per day through supplements and foods showed a resulting decreased risk for high blood pressure of 45% in the younger group and 39% in the older group.

How Folic Acid Works

It's well established that folic acid helps protect blood vessel health and that hypertension is most often a symptom of compromised vessel health. However, according to Michael Hirt, MD, medical director, Center for Integrative Medicine at Encino-Tarzana Regional Medical Center and associate clinical professor at UCLA School of Medicine, folic acid's unique magic is in its ability to reduce dangerous homocysteine levels.

Nowhere do the study reports mention homocysteine, an amino acid in the bloodstream created by the liver. High levels of homocysteine may be related to genetic predisposition or to a deficiency in folic acid, B-12 or B-6. Homocysteine in elevated amounts damages blood vessel health and increases risk for stroke and heart attack. There are no symptoms that flag the presence of elevated homocysteine, and folic acid is the only thing that reduces homocysteine levels.

Consequently, to avoid the risks caused by elevated homocysteine levels and to lower your risk for high blood pressure, it is crucial to get plenty of folate on a regular basis. The good news is that even if you don't want to take a supplement, folate is easily available in foods, says Dr. Hirt, especially in dark green, leafy vegetables such as spinach, kale, Swiss chard, romaine lettuce and others. It's also found in broccoli and cauliflower. Eat three or more servings a day of these. Many grain products are supplemented with folic acid, and virtually all multivitamins now contain 400 mcg of it. Note: You should not take more than 1,000 mcg a day in supplements... however, you can eat any amount of it in foods without risk.

Men take note: Dr. Hirt says that men benefit equally from folic acid.

When you get your cholesterol checked, ask to have your homocysteine level tested as well. If you find that your level is high in spite of regular folate consumption, Dr. Hirt says this may reflect a problem with metabolizing it. Speak to a medical professional who is properly trained in nutritional supplementation about whether you need to supplement, and if so, by how much. High levels of folic acid supplementation have been linked to tumor growth, so you need proper guidance. Additionally, folic acid should be taken with B-12 and B-6 to be effective.

Be well, Carole Jackson, Bottom Line's Daily Health News, August 15, 2005

Source:

No Fooling:   Michael Hirt, MD, medical director, Center for Integrative Medicine, Encino-Tarzana Regional Medical Center, and associate clinical professor, UCLA School of Medicine, California.

More Testing of Vitamin B-12 Deficiency Urged

 ProHealthNetwork.com   03-14-2005

By Linda Stahl, The Courier-Journal

The medical community needs to do a better job of detecting vitamin B-12 deficiency, said Florian Thomas, associate professor of neurology at Saint Louis University.

"Just this small step would have broad health implications," said Thomas, who said a blood test commonly used to measure B-12 isn't sensitive enough and should be supplemented with another test. B-12 is needed to produce red blood cells and to maintain a healthy nervous system. It is important for every cell and system in the body, including the blood and nervous system.

It is essential for formation of myelin, the fatty sheath that surrounds nerves.

To measure B-12, health providers commonly draw blood and send it to a lab for measurement of B-12 values, which are measured in picograms per milliter (pg/ml).

Normal is considered 170 to 200 pg/ml, Thomas said. But he and his colleagues at Saint Louis University have studied patients with normal levels of B-12 who nonetheless have B-12 deficiency.

Second test useful

Thomas is urging doctors who think their patients lack the vitamin because of symptoms to also test their blood for methylmalonic acid (MMA), a natural compound in the body that increases when B-12 is lacking.

He said the cost of such additional testing wouldn't be great, with a regular blood test for B-12 running about $20 and a blood test for MMA running about $40.

"The usual way of diagnosing B-12 deficiency may be inadequate because it underestimates the frequency of the problem, which is present in up to 20 percent of the elderly," Thomas said.

He said problems brought on by B-12 deficiencies in the elderly would cost only pennies a day to prevent with a B-12 vitamin pill.

Other authorities, including authors of the University of California Berkeley Wellness Letter, recommend that doctors check to see if vitamin B-12 is lacking if a patient develops such symptoms as dementia, hallucinations, memory loss and confusion.

B-12 deficiency can occur at any age, but is more common in the older population and can mimic other disorders, including Alzheimer's disease, Thomas said.

Risks of low B-12

B-12 deficiency can cause:

Impaired memory
Dementia
Irritability
Depression
Weakness
Pain, numbness or tingling in the hands and feet
Lack of coordination

According to the National Institutes of Health, other symptoms and problems associated with B-12 deficiency include:

Anemia
Fatigue
Constipation
Loss of appetite
Weight loss

In infants, B-12 deficiency can cause failure to thrive, movement disorders, delayed development and a type of anemia.

Daily dose

The National Academy of Sciences recommends that adults over 50 get 6 to 12 micrograms of B-12 a day and advises taking supplements or eating foods, such as breakfast cereals, fortified with B-12. Fortified foods release the B-12 more easily than foods in which the vitamin naturally occurs.

Thomas sees no harm in taking a higher dosage than recommended in supplement form, saying there is "no fear of overdosing" because the vitamin is water-soluble.

Thomas also noted that elderly patients undergoing surgery or dental work where laughing gas, or nitrous oxide, is administered are in special danger if they have undiagnosed B-12 deficiencies.

Nitrous oxide can inhibit the use of B-12 by the body when stores of it in the tissues are low. Thomas thinks that surgeries and dental practices that use laughing gas should routinely test patients in advance for B-12 deficiencies.

Otherwise, within a week a person with low B-12 stores who gets laughing gas might exhibit symptoms such as confusion and memory loss.

Who needs tests

Thomas urged that patients be rigorously tested before surgery to see if they have low B-12 stores and tested after age 65 every two years. Thomas and Saint Louis University researchers Dr. Chitharanjan Rao and Dr. John Selhorst also have found that it can be difficult to distinguish multiple sclerosis from B-12 deficiency.

Some medical personnel, young adults and teenagers abuse nitrous oxide, buying it from baking supply stores or using the gas contained in whipped-cream dispensers.

Nitrous oxide abuse resulting in B-12 deficiency should be considered in young adults with unusual neurological conditions, Thomas said.

Copyright 2004 The Courier-Journal.

Low Vitamin B12 Is Associated With Poorer Memory In Older People With High Risk For Alzheimer's

WASHINGTON -- Among healthy people over the age of 75 who have the genotype associated with higher risk for Alzheimer's, low levels of vitamin B12 are associated with significantly worse performance on memory tests. This finding is published in the April issue of Neuropsychology, which is published by the American Psychological Association (APA).

David Bunce, PhD, a psychologist at Goldsmith's College, University of London, Miia Kivipelto, PhD, MD, of the Aging Research Center at the Karolinska Institute in Stockholm and the Stockholm Gerontology Research Center, and Åke Wahlin, PhD, a psychologist at the University of Stockholm, conducted the study as part of a long-term multidisciplinary project that follows older people living in Stockholm's Kungsholmen parish.

Scientists already knew of a genetic predisposition for Alzheimer's disease, and that low levels of two B vitamins-- B12 and folate--were also linked to problems. However, few had examined nutrition and genotype together relative to cognition, to reflect what real people carry into old age a mix of inborn traits and environmental factors such as nutrition, including undiagnosed vitamin B deficiencies.

The apolipoprotein E gene, which moves cholesterol in the body, has a version called the T4 allele. Carried by perhaps 15 percent of the population, it is a risk factor for dementia. Current data collected over a six-year period suggests that nearly one out of four carriers with one copy of this allele and nearly half carrying two copies will develop Alzheimer's disease. Non-carriers also can get Alzheimer's.

Carriers of the T4 allele have smaller hippocampi, brain areas associated with memory, so the researchers wanted to measure how an additional physiological shortfall such as low Vitamin B, affected this particular group -- given that reduced B12 and folate have been linked generally with diminished memory and increased risk for Alzheimer's. Perhaps 10 percent of adults aged 75 years and older have low B12 or folate.

Bunce, Kivipelto and Wahlin studied 167 healthy older people, averaging nearly 83 years old. First, they checked blood samples for vitamin levels and genotype. Some 82 participants had low B12 (28 with the T4 allele; 54 without). The researchers then tested episodic memory, varying the test conditions to make them as sensitive as possible to underlying disorder.

Among carriers of the T4 ApoE allele, people with normal B12 levels recalled a greater number of words. More time to encode (five as opposed to two seconds) also was associated with greater recall. More than doubling encoding time strengthened memory more for the T4-low vitamin group than it did for other participants.

A significant difference showed up in the experiment's most demanding condition, when participants had just two seconds to encode words. In that situation, the high-risk genotype plus low B12 levels was significantly associated with poorer memory.

The findings endorse a complex model of vulnerability in which genetic and non-genetic factors interact. According to the authors, "T4 ApoE carriers may derive relatively greater cognitive benefits from B12 and folate supplements. Supplement treatment is relatively inexpensive and may be required as part of preventive health regimes for older persons."

Source: American Psychological Association,  April 5, 2004

Web address: http://www.sciencedaily.com/releases/2004/04/040405085355.htm

Increased B12 levels could ward off dementia

By Stephen Daniells

11/16/2007- Increased levels of vitamin B12, but not folate, may reduce the rate of age-related cognitive decline and dementia, suggests a new study from Oxford.

The longitudinal cohort study followed 1648 participants for 10 years, and found a doubling in holotranscobalamin (holoTC) concentrations was associated with a 30 per cent slower rate of cognitive decline. The study is published in the American Journal of Clinical Nutrition.

Moreover, increased levels of the amino acid homocysteine doubled the risk of dementia or cognitive impairment, report the researchers, led by Robert Clarke from the University of Oxford.

Previously, epidemiological studies have reported that high levels of the amino acid homocysteine are associated with suspected or confirmed dementia. Indeed, the Framingham study reported that people with homocysteine levels above 14 micromoles per litre of serum had twice the risk of dementia.

This has led to the hypothesis that by lowering circulating levels of homocysteine by B vitamin supplements, the risk and occurrence of dementia could be reduced. However, intervention trials have reported mixed results, and the subject remains debatable.

The new study measured serum concentrations of vitamin B-12, holoTC, homocysteine, methylmalonic acid (MMA), and folate of the participants in 1995, and related this to measures of cognitive function assessed on three occasions during the ten year study. Mental function was tested using the Mini-Mental State Examination.

Clarke and co-workers report that doubling holoTC levels from 50 to 100 picomoles per litre was associated with a 30 per cent slower rate of cognitive decline. Folate levels did not impact cognitive performance.

Furthermore, a doubling of homocysteine levels, from 10 to 20 micromoles per litre, or MMA levels, from 0.25 to 0.50 micromoles per litre, was associated with a rapid decline of cognitive function of over 50 per cent.

The researchers, called for randomised trials to investigate the potential benefits from vitamin B-12 supplementation for prevention of dementia.

The B-Vitamin Treatment Trialists' Collaboration should soon be better able to address the link between B-vitamins, homocysteine levels, and cognitive function. The effects of three to seven years of treatment with B vitamins on cognitive function should eventually be available on about 20,000 of the 50,000 participants with previous cardiovascular or renal disease from 12 large homocysteine-lowering trials.

Vitamin B12, also known as cobalamin, is only found in food of animal origin, including meat, milk and eggs.

The recommended daily intake of vitamin B12 in Europe is 2.5 micrograms.

Source: American Journal of Clinical Nutrition; November 2007, Volume 86, Number 5, Pages 1384-1391
"Low vitamin B-12 status and risk of cognitive decline in older adults"
 

From:   [http://www.nutraingredients-usa.com/news/ng.asp?n=81412&m=1NIUN16&c=eesdyjwxcwxhnwg]