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James F. Slattery wrote: > I am a PD sufferer, and am trying to continue working. I have on/off > times which I find difficult to govern. > In an area of the Web on alternative medecine, I saw a claim that the > amino acids L-TYROSINE and L-GLUTAMATE were beneficial to PD sufferers, in > that they aided the uptake of l-dopa. > In view of your comments about "... large neutral amino acids...", could > you comment on this. (I know nothing of the subject.) Jim, To the best of my understanding, in the early stages of PD the brain produces dopamine in reduced amounts. The Sinemet boosts this amount up to normal, so a steady supply of dopamine reaches the brain, and "off" times don't occur. Later on, the brain ceases to produce dopamine at all, and must rely totally on Sinemet. I believe it is at this time that off times start to occur. The problem at this point is that the six large neutral amino acids (isoleucine, leucine, valine, phenylalanine, tryptophan, and tyrosine), five of which are essential aminos, must cross the cells of the intestine to get into the blood. Once in the blood, they must cross the blood-brain barrier to get into the brain. Sinemet also must cross the intestine and the blood-brain barrier. And the LNAAs and sinemet use exactly the same carrier system to get across. Therefore, a meal high in protein combined with Sinemet can seriously interfere with Sinemet absorption, particularly at the brain. Research indicates that about two-thirds of people who experience "on-off" periods can benefit by adjusting their protein intake. Others do not seem to benefit. As Camilla pointed out, though, there is some confusion between sinemet and Sinemet CR. Sinemet CR (controlled-release) is designed to be released slowly into the blood over a long period of time, and is best taken with food. Regular Sinemet, however, is best taken 30-60 minutes before a meal. Some people use both Sinemet and Sinemet CR; these should take Sinemet on an empty stomach and Sin. CR with meals. For those wishing to adjust their protein intake, there are 3 ways currently considered feasible. 1) Ingest the RDA for protein (.8 grams protein per kg body weight) spread evenly throughout the day; 2) ingest the RDA for protein, taking almost all of it in the evening to increase daytime mobility; 3) ingest the RDA for protein spread throughout the day, in a 7-to-1 ratio with carbohydrate. This should be discussed with one's physician first. For most people, it would be helpful to work closely with a registered dietitian, who can determine individual protein needs, and provide accurate information on the amounts of protein and carbohydrate in foods. My own theory is that plant protein may be a good choice for part of the protein ingested. This is because plant protein contains a high ratio of carbohydrates to protein, whereas, meat, fish, poultry contain almost no carbohydrate. Carbohydrate breaks down into glucose in the gut, and large amounts of glucose in the blood cause insulin release. Insulin scavenges amino acids from the blood and may help lower the competition between aminos and Sinemet. Regarding the alternative medicine website, I have not seen any scientific references to the effect that L-tyrosine/L-glutamate would assist l-dopa uptake. I am in favor of alternative medicine where it is medically sound; however, much quackery abounds, and I recommend great caution here. Perhaps others on the list have heard more about this; I would appreciate any information. -- Kathrynne Holden, MS, RD Editor-in-Chief, "Spotlight on Food--nutrition news for people 60-plus" Tel: 970-493-6532 Fax: 970-493-6538 http://www.fortnet.org/~fivstar You may wish to contact: Better Business Bureau of the Mountain States, < [log in to unmask]> for further information.