NUTRITION NEWS
NUTRITION NEWS
The Zen Of L-theanine
Sales of pharmaceutical anti-depressants and anti-anxiety drugs totaled over $5 billion in 1998, and these numbers continue to increase. An estimated 65% of adults experience stress or anxiety.
Anything that calms people down is welcome in Japan. In 1949, Japanese researchers isolated L-theanine in green tea leaves as the ingredient that offsets the hyper effect of caffeine.
In 1964, Japan approved the use of L-theanine in all food except baby food. L-theanine exerts subtle changes in biochemistry that help increase concentration and clear, focused thought, creating deep relaxation without sedation. It is estimated that six to eight cups of green tea is equivalent to 200 mg to 400 mg of L-theanine.
During a recent study, test subjects ranging from ages 18 to 22 were divided into high-anxiety and low-anxiety groups using the Manifest Anxiety Scale. Over a two-month period, each volunteer was given a test solution of water containing either 50 mg or 200 mg of L-theanine. Within 30 to 40 minutes of taking the L-theanine solution, the volunteers in both groups experienced a relaxing effect. Researchers attribute this to alpha brain waves that create a state of deep relaxation while maintaining mental alertness.
In an experiment conducted by Dr. Hihehiko Yokogoshi, PhD, and Dr. Takehiko Terashima, PhD, at the Laboratory of Nutritional Biochemistry in Shizuoka, Japan, it was discovered that L-theanine increases blood levels of gamma-aminobutyric acid (GABA), which helps maintain optimum levels of the neurotransmitters dopamine and serotonin in the brain.Dopamine is similar to adrenaline, and affects brain processes that control movement, emotional response, and the ability to experience pleasure and pain.
Serotonin controls the pain threshold, mental alertness, and sense of well being. Low levels of serotonin can cause sleep disturbance, increased anxiety, and irritability.In a study done in 1999 at the University of Shizuoka, Japan, several other unique properties of L-theanine were found. In addition to facilitating relaxation, L-theanine may benefit blood pressure regulation, learning retention, mental clarity, concentration, and immunity.
As an added benefit, L-theanine does not cause drowsiness or other side effects, as do some herbs and most pharmaceutical drugs. Unlike most amino acids, L-theanine can be taken with or without food, at any time of day.
Reference: Bioscience Biotech Biochemistry, 2000; 64:287-93.
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CoQ10 May Slow Down Parkinson's Disease
Results of the first placebo-controlled clinical trial of CoQ10 suggest that this nutrient can slow the progression of symptoms in patients with early-stage Parkinson's disease (PD).
PD is a chronic, progressive neurological disease that affects about 500,000 people in the U.S. The study, led by Dr. Clifford Shults, MD, of the University of California, San Diego School of Medicine, looked at a total of 80 PD patients across the U.S. to determine if CoQ10 is safe and if it can slow the rate of functional decline. "This trial suggested that CoQ10 can slow the rate of deterioration in Parkinson's disease," said Dr. Shults.
All of the patients who took part in this study had the three primary features of PD-tremor, stiffness, and slowed movements, and had been diagnosed with the disease within five years of the time they were enrolled. After initial screening and blood tests, the patients were divided into four groups. Three of the groups received CoQ10 at three different doses: 300 mg per day, 600 mg per day, and 1,200 mg per day, along with vitamin E, while a fourth group received a matching placebo that contained vitamin E only. Each participant received an evaluation one month later, and every four months thereafter for a total of 16 months.During the study period, the group that received the largest dose of CoQ10, 1,200 mg per day, had a 44% reduction in the progression of their condition compared to the placebo group. The greatest effect was on activities of daily living such as eating and dressing. The groups that received 300 mg per day and 600 mg per day developed slightly less disability than the placebo group, but the effects were less beneficial than those in the high-dose CoQ10 group.
"The results of this study suggest that doses of CoQ10 as high as 1,200 mg per day are safe and may be more effective than lower doses," in slowing the progression of PD, said Dr. Shults.
Reference: Archives of Neurology, 2002; Vol. 59, No. 10, 1541-50.
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Magnesium And Blood Pressure
The most recent National Health and Nutrition Examination Survey conducted by The National High Blood Pressure Education Program estimated 42.3 million people in the U.S. have hypertension.
Researchers at Case Western Reserve University in Cleveland, OH, report in Nature that magnesium works to maintain healthy blood pressure by facilitating the relaxation and dilation of the smooth muscle cells that control the diameter of blood vessels. High blood pressure results from the contraction of these blood vessels. The researchers hope that the findings will be used in future studies to help understand the role magnesium plays in decreasing high blood pressure, heart failure, and stroke.
"Research of this kind may help explain why some therapies such as magnesium supplements are important in the prevention and management of hypertension or heart failure," said Dr. Jianmin Cui, PhD, the lead researcher in the study.
High blood pressure often has no symptoms, and is defined as a reading greater than 140/90 mmHg. Healthy lifestyle changes that facilitate lower blood pressure include regular exercise, weight loss, stopping smoking, and cutting back on alcohol, coffee, salt, and sugar.
Reference: Nature, August 2002; 418, 876-80.
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Conjugated Linoleic Acid And Weight Loss
New data from the Centers for Disease Control and Prevention show more than 30% of adults in the U.S. are obese. According to a recent study published in the Journal of the American Medical Association, this is an 8% increase from 1994. There are also more extremely obese adults, now 4.7% of the population versus 2.9% in the 1994 study. The percentage of overweight American adults has also risen from 55.9% to 64%.
A recent double-blind, placebo-controlled study published in The Journal of Nutrition finds that conjugated linoleic acid (CLA) reduces body fat in people that are overweight. This is the largest scientific study to date showing that CLA reduces the weight of fatty tissue in the body and preserves muscle tissue. "We found an average reduction of six pounds of body fat in the CLA group compared to placebo," said Dr. Ola Gudmundsen, PhD, chief executive officer, Scandinavian Clinical Research AS, Norway.
In the study, 60 overweight people were randomly assigned to take a placebo or CLA for twelve weeks. The main objectives were to investigate the effects of different doses of CLA, from 1.7 grams to 6.8 grams per day, compared to placebo. Results showed a measurable reduction in the body's fat mass. The study indicated that 3.4 grams of CLA per day is enough to obtain all the beneficial effects on body fat. The group given the highest dose, 6.8 grams of CLA per day, also experienced a slight increase in lean body mass. For the study, investigators used Tonalin CLA, available in several brands.
Reference: The Journal of Nutrition, 2000; Vol. 130, No. 12.
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Vitamin E Reduces Post-Workout Soreness
The results of a recent study in healthy men find that vitamin E may ease aches and pains after exercise. Lead researcher Dr. Jennifer Sacheck, of Tufts University, believes vitamin E acts as an antioxidant, mopping up the damaging byproducts of a strenuous workout.The physically fit may not need extra vitamin E after exercise but, "if you are one to experience a great deal of soreness and fatigue after a workout, especially those people who do not exercise habitually, vitamin E might be of benefit to help combat soreness and exercise-induced stress," said Dr. Sacheck.
During exercise, as the body increases its use of oxygen, byproducts of oxygen metabolism, called free radicals, can do damage to muscle tissue. This damage can result in soreness and fatigue after strenuous exercise.
In the study, two groups of men aged 23 to 35, and 66 to 78 took either a placebo or a 1,000 IU supplement of vitamin E every day for three months. Rates of post-exercise soreness were compared before and after the study. The researchers found that the athletes' soreness and muscle damage was more subdued in the vitamin E group. Young men saw the most benefit, but older men also benefited. It is not known whether vitamin E would work as well in young women, as naturally-occurring estrogen may reduce the antioxidant effect. Menopausal women may have better results.
Dr. Sacheck also noted that while her team used 1,000 IU per day for the study, the average individual could probably get the same benefit from doses of 200 IU to 400 IU of vitamin E per day.
Reference: Annual Conference on Experimental Biology, 2002.
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Omega-3 And Brain Development
Pregnant women who eat more docosahexaenoic acid (DHA), an omega-3 fatty acid found in fish, give their babies a better chance of mature brain development reports the September 2002 issue of the American Journal of Clinical Nutrition. Seventy percent of all brain cell development takes place during gestation. "The results of this study are strongly suggestive of the importance of DHA levels during the last trimester," stated study author Dr. Evelyn Thoman.
Researchers also found that mothers with more DHA in their blood had babies with better sleep patterns in the first 48 hours after delivery, compared to babies whose mothers consumed less DHA. Infant sleep patterns seem to reflect the maturity of the nervous system, and have been associated with more rapid development in the first years of life. DHA is one of the nutrients passed from mother to fetus across the placenta.
During the study, Dr. Thoman and her colleagues measured the levels of DHA in the blood of 17 women when they delivered their babies. The investigators then monitored the sleep patterns of the babies during the first two days of life, using a sensor pad to record how the baby was breathing and moving while asleep.
This current study is not the first to suggest a link between infant DHA intake and brain development. Previous research has shown that babies who are fed mother's milk, which contains DHA, develop more mature brain cells than those that are fed formula only.
Reference: American Journal of Clinical Nutrition, 2002; 76:608-13.
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Black currant seed oil stimulates immune function in older people, according to a study by Dr. Dayong Wu, PhD, of Tufts University.
In this double-blind, placebo-controlled study, 40 healthy volunteers aged 65 or older were given 750 mg of black currant seed oil or 750 mg of soybean oil six times per day for two months, for a total of 4.5 grams per day.
Researchers evaluated the immune function by measuring skin response to an antigen called tetanus toxoid. Response to this toxin generally declines with age. Subjects that took the black currant seed oil showed a 28% greater skin response after two months. The response in the placebo group was unchanged.
Reference: American Journal of Clinical Nutrition, 1999; 70:536-43.
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Written by: EcoMall
Disclaimer: These statements on this site have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease, and is for educational purposes only. For any serious illness or health related disorders please consult your physician.
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