From Nutri Ltd
Choline is an essential nutrient. It can be synthesised in the body but, to sustain health, it must be consumed in the diet. The majority of choline is found in phospholipids (the fatty part of the membranes surrounding cells).
Choline has a number of vital roles.
It is used in the synthesis of the phospholipids, phosphatidylcholine and sphingomyelin, which are structural components of human cell membranes, as well as precursors for the intracellular messenger molecules (diacylglycerol and ceramide). Choline itself also produces two metabolites - platelet activating factor (PAF) and sphingophosphorylcholine -both known to be cell signalling molecules.
One of choline’s most well known roles is as the precursor of the neurotransmitter acetylcholine, which is vital to memory formation and muscle function.
In the liver, fat and cholesterol are packaged into proteins, called very low density lipoproteins (VLDL), for transport through the blood to tissues that require them. Phosphatidylcholine is a required component of VLDL particles, and therefore, without adequate phosphatidylcholine fat and cholesterol will accumulate in the liver.
When choline reacts with oxygen, betaine is produced, a metabolite that is a major source of methyl groups. Methylation reactions (the addition of a methyl group to a molecule) regulate gene expression. Methyl groups from betaine may be used to convert homocysteine to methionine, which can be extremely beneficial, as elevated homocysteine is linked to cardiovascular disease.
Men and women fed intravenously (IV) with solutions that lacked choline have developed fatty livers and signs of liver damage that resolved when choline was provided. One study in 57 adults who were fed choline-deficient diets under controlled conditions found that 77% of men, 80% of post- menopausal women, and 44% of pre-menopausal women developed fatty liver, liver damage, and/or muscle damage. A recent study in 51 men and women reported that a choline-deficient diet induced DNA damage.
More research is needed to determine the role of choline in the developing brain and whether choline intake is useful in the prevention of memory loss.
ttle is known about dietary requirements for choline as humans can synthesize choline in small amounts by converting the phospholipid phosphatidylethanolamine to phosphatidylcholine. Three methylation reactions are required, each using the compound S-adenosyl methionine (SAM), which is itself synthesised from the amino acid methionine, as a methyl group donor. Oestrogen stimulates the synthesis of choline via the phosphatidylethanolamine N-methyltransferase (PEMT) enzyme. The Linus Pauling Institute recommends 550 milligrams (mg)/day for adult men and 425 mg/day for adult women.
Choline supplements are generally safe, however, high doses (10 to 16 grams/day) have been associated with a fishy body odour, vomiting, salivation, and increased sweating. The fishy body odour results from excessive production and excretion of trimethylamine, a metabolite of choline. Individuals with liver or kidney disease, Parkinson's disease, depression, or a genetic disorder known as trimethylaminuria (fish odour syndrome) may be at increased risk of adverse effects.
Phosphatidylcholine, a major component of lecithin, contains about 13% choline by weight and is the form in which choline most commonly appears in food. Lecithins added during food processing may increase the daily consumption of choline by about 115 mg/day. Milk, eggs, liver, and peanuts are especially rich in choline with one egg containing about 126mg of choline.
Science Supports the Natural Route for a Healthy Menopause
The process whereby the ovaries stop producing eggs for fertilization and menstruation ends is known as the menopause. Most women experience it between 45 and 55 years of age. As levels of oestrogen and progesterone drop, symptoms such as hot flushes, vaginal dryness, urinary incontinence, mood fluctuations, anxiety, depression and bone loss can occur. To help control symptoms and decrease the risk of developing osteoporosis women often use Hormone Replacement Therapy (HRT). However, HRT carries an increased risk of breast cancer, cardiovascular disease, stroke and deep vein thrombosis. Many women are now seeking natural alternatives to help them through the menopause without risk. Two new scientific publications support the use of two such established natural supplements, black cohosh and soy isoflavones, by post-menopausal women.
Black cohosh is popular in the treatment of menopausal symptoms such as hot flushes, mood disturbances, excessive sweating, palpitations, and vaginal dryness. Several studies have reported that black cohosh improves menopausal symptoms for up to six months, although the evidence has been mixed. The influence of black cohosh on oestrogen levels in the breast has not previously been examined. In a new study, post-menopausal women took an extract of black cohosh (BCE) for 12 weeks, followed by a 12 week period off the supplement to allow it to wash out of the system. Women taking BCE with 2.5% triterpenes (compounds that are building blocks of steroid hormones such as oestrogen and progesterone) experienced relief of menopausal symptoms, with reversion toward baseline after washout. The content of triterpenes, and thus the effectiveness, of commercial BCE was found to vary significantly. Perhaps most importantly BCE was found to have no effect on circulating levels of oestrogen nor on breast-specific estrogenic markers. The authors conclude that “BCE standardised to 2.5% triterpenes relieved menopausal symptoms without systemic or breast-specific estrogenic effects”.
Click here to view the study abstract.
Soy beans and products made from them are one of nature’s richest sources of phytoestrogens, plant compounds that are structurally similar to oestrogen. As a result of its estrogenic structure, soy has traditionally been used to help relieve menopausal symptoms including osteoporosis (“brittle bone disease”). A new meta-analysis, examining nine randomised-controlled trials, concluded that supplementation with isoflavones (phytoestrogens found in soy) significantly inhibits bone resorption (breakdown) and stimulates bone formation. These favourable effects occur even if less than 90 mg/day of isoflavones are consumed or the intervention lasts less than 12 weeks. This is strong support for the use of soy by post-menopausal women to help reduce the risk of osteoporosis.
Click here to view the study abstract.
Carefully chosen supplements, used under professional supervision, can help reduce the health risks associated with the menopause.
Another Use for the Polyphenols in Green tea?
Indian scientists are looking into the potential of green tea polyphenols to stop the oxidation of fat in meat products. This would help to extend the shelf- life and prevent 'off' flavours.
There are many health benefits attributed to the humble cup of tea. Green tea in particular has been associated with a lower risk of certain cancers, improved heart health, weight loss, and protection against Alzheimer's.
Now, scientists are looking at whether the beneficial polyphenols may also have a role to play in food preservation.
The new study tested a green tea extract on fresh meat. Lead author K.V. Kumudavally reported that the polyphenol-rich extract inhibited microflora spoilage by up to four days, without adversely affecting the sensorial and physical quality of the meat.
The researchers wrote, "Since green tea is consumed by people as a daily beverage all over the world, extracts of green tea may be safe to use in food systems to extend the shelf life".
Source: Food Chemistry (Elsevier)1 March 2008, Volume 107, Issue 1, Pages 426-433, doi: 10.1016/j.foodchem.2007.08.045"Green tea - A potential preservative for extending the shelf life of fresh mutton at ambient temperature (25 degrees Celsius)"Authors: K.V. Kumudavally, H.S. Phanindrakumar, A. Tabassum, K. Radhakrishna and A.S. Bawa
New study shows probiotics may help to boost the immune systems of elite endurance athletes
Endurance athletes undergoing strenuous training are reported to be more susceptible to upper respiratory tract infection (URTI) linked to the role of strenuous exercise in suppressing the immune system.
Intense exercise suppresses the immune system for several hours. It does so by robbing the immune system of two of its principal fuels – glucose and the amino acid glutamine – and by stimulating cortisol release. One of the many effects of high cortisol levels is a reduction in immune system activity. This increases a runner’s risk of contracting infections and it also hampers recovery, as the immune system plays an important role in healing muscle damage after exercise.
People are becoming increasingly aware of the health benefits associated with probiotics, including improved intestinal health and immune system stimulation. In this recent study, a daily probiotic capsule was found to enhance the activity of T cells, which are key players in the immune system.
David Pyne and his colleagues from the Australian Institute of Sport followed 20 elite, endurance athletes during four months of intensive winter training. The athletes were randomly assigned to receive either a daily probiotic supplement or placebo. After 28 days of receiving either the probiotic or placebo, they received nothing for one month (washout period) before crossing over to the other intervention. By the end of the study all the athletes had each had the probiotic and placebo formulations.
The researchers reported no difference in running performance as a result of placebo or probiotic supplementation. On the other hand, the number of days of symptoms of respiratory infection was halved when the athletes took the probiotic, compared to placebo. The severity of the symptoms was also reduced when receiving probiotics.
The blood samples showed that blood levels of interferon gamma, an important component of the body's immune response, were doubled when the subjects received probiotics, compared to placebo. The researchers speculated that the benefits appeared to be mediated via an enhancement of the functioning T-lymphocyte function.
"In combination with the recent report that probiotic supplementation reduced the duration of gastrointestinal symptoms in marathon runners in the 2 weeks after the race [Int J Sport Nutr Exer Metab, 2007, Vol. 17, pp. 352-363], our findings point to the potential benefits of this form of nutritional intervention," wrote the authors.Source: British Journal of Sports Medicine
Published online ahead of print, doi 10.1136/bjsm.2007.044628"Oral administration of the probiotic Lactobacillus fermentum VR1-003 and mucosal immunity in endurance athletes"Authors: A.J. Cox, D.B. Pyne, P.U. Saunders, P.A. Fricker