Choline / homocysteine / heart disease

ironjustice@aol.com · medicine forum Guru Joined: 28 Apr 2005 Posts: 1522

Increased choline intake could cut CVD risk, suggests study

By Stephen Daniells

22/06/2006 - Increased intake of choline, a nutrient found in meat,
milk and eggs, can reduce circulating levels of homocysteine, an amino
acid linked to increased risk of heart disease, says a study.

"Our study adds further evidence that intakes of less than one gram
choline or betaine per day can reduce homocysteine concentrations in a
free-living population," wrote lead author Eunyoung Cho from Harvard
Medical School.
Few studies have investigated the effects of the nutrient in terms of
disease prevention because food composition databases were not
available until only recently.

The new study has taken advantage of these databases and reports that
people with increased intake of choline, and its oxidation product
betaine (found naturally in vegetables such as spinach), have lower
levels of homocysteine.

The amino acid homocysteine has been linked by epidemiological studies
to an increased risk of cardiovascular disease. A meta-analysis in the
British Medical Journal (Vol. 325, pp. 1202-1208) of genetic and
prospective studies reported that a 3 micromole per litre decrease in
homocysteine levels was associated with a decrease in the risk of
ischemic heart disease of 16 percent.

The Harvard study, published in the American Journal of Clinical
Nutrition (Vol. 83, pp. 905-911), analysed the dietary intake of 1960
volunteers (1040 women) with an average age of 54 using a validated
130-item food frequency questionnaire.

Choline and betaine intake was calculated using the Harvard University
Food Composition Database, the US Department of Agriculture's choline
database, and values published in 2003 in the Journal of Nutrition
(Vol. 133, pp. 1302-1307).

The researchers found that the highest choline intake (401 milligrams
per day) was associated with a nine per cent lower plasma concentration
of homocysteine, compared to the lowest intake group (234 milligrams
per day).

When betaine was counted along with choline, a similar reduction in
homocysteine level was observed (9.2 per cent) when comparing the
highest intake groups (689 milligrams per day) with the lowest intake
group (383 milligrams per day).

The results took into account possible complicating factors such as
age, sex, smoking, alcohol, hypertension, and intakes of B-vitamins.

Increased intake of B-vitamins, and particularly folate/folic acid, has
been reported to reduce homocysteine levels, and protect against heart
disease.

"Intakes of choline and betaine predicted plasma homocysteine
concentrations independent predictors, including intakes of folate and
B vitamins," said the researchers.

The mechanism behind the benefits is proposed to be the oxidation of
choline to betaine, which then donates a methyl group to homocysteine
to form methionine. This mechanism, say the researchers, is confined to
the kidney and livers.

This also suggests, said Cho, that even if folate intake is low,
homocysteine levels can be reduced by having an adequate intake of
choline and betaine.

Recommended daily intakes of choline were set in 1998 at values of 550
milligrams per day for men and 425 milligrams a day for women. The mean
intake of the entire study population was found to be 313 milligrams a
day, indicating this study population were not consuming adequate
amounts of the micronutrient.

The results appear to be in line with intervention studies using high
dose betaine or choline supplementation, which have reported
homocysteine reductions of up to 20 per cent (betaine, 1.5 to 6 grams
per day).

Red meat was reported to be the richest source of choline, giving about
14 per cent of the daily intake. Spinach was reported to be the
participants' richest source of betaine, accounting for over 25 per
cent of the daily intake.

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<<snip>>
Lecithin may therefore be the method of choice for
accelerating acetylcholine synthesis by increasing the availability of
choline, its precursor in the blood.

<<snip>>

Lancet. 1977 Jul 9;2(8028):68-9. Related Articles, Links

Lecithin consumption raises serum-free-choline levels.

Wurtman RJ, Hirsch MJ, Growdon JH.

Consumption of choline by rats sequentially increases serum-choline,
brain-choline, and brain-acetylcholine concentrations. In man
consumption of choline increases in levels in the serum and
cerebrospinal fluid; its administration is an effective way of treating

tardive dyskinesia. We found that oral lecithin is considerably more
effective in raising human serum-choline levels than an equivalent
quantity of choline chloride. 30 minutes after ingestion of choline
chloride (2-3 g free base), serum-choline levels rose by 86% and
returned to normal values within 4 hours; 1 hour after lecithin
ingestion, these levels rose by 265% and remained significantly raised
for 12 hours. Lecithin may therefore be the method of choice for
accelerating acetylcholine synthesis by increasing the availability of
choline, its precursor in the blood.

PMID: 69151 [PubMed - indexed for MEDLINE]

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