Contrary to popular belief, the consumption of animal foods may actually decrease tryptophan levels in the brain. Carbohydrates, on the other hand, can boost transport across the blood-brain barrier, which has been used to explain premenstrual cravings.
Tryptophan is one amino among many found in proteins, and they “”compete with one another for transport across the blood-brain barrier into the brain. And since tryptophan is present in most animal proteins in relatively small quantities it gets muscled out of the way. If you eat plant foods, though, the carbohydrates cause a release of insulin, which causes your muscles to take up the nontryptophan amino acids as fuel, and so your tryptophan can be first in line for brain access.
Animal foods can even make things worse: “When tryptophan is ingested as part of a protein meal, serum tryptophan levels rise but brain tryptophan levels decline (Fernstrom and Faller 1978). due to the mechanism of transport used by tryptophan to cross the blood–brain barrier.”
The tryptophan levels in those given a high protein turkey egg cheese breakfast dropped… whereas, in the waffle-OJ group, their trytrophan levels went up.
This may actually explain the carbohydrate cravings one sees in PMS—your brain may be trying to get you to boost tryptophan levels to feel better. “Consumption of a carbohydrate-rich. protein-poor evening test meal during the premenstrual period improved depression, tension, anger, confusion, sadness, fatigue, alertness, and calmness scores—significantly--among patients with premenstrual syndrome.”
“Because synthesis of brain serotonin, which is known to be involved in mood and appetite, increases after carbohydrate intake, premenstrual syndrome subjects may overconsume carbohydrates in an attempt to improve their dysphoric mood state.”
Ideally, though, it would be more than just carbs—we'll cover the ideal mixture in tomorrow;s video-of-the-day
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Kerry Skinner.
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This is the third of a four-part series (mentioned in Uprooting the Leading Causes of Death) on natural ways to boost serotonin in the brain. Wednesday's video-of-the-day Human Neurotransmitters in Plants noted that plants themselves can contain serotonin. Yesterday's The Wrong Way to Boost Serotonin was a cautionary tale about tryptophan supplements, and Monday we'll close with the Best Way to Boost Serotonin. The arachidonic acid in animal foods may also contribute to negative mood states through an inflammatory mechanism. See, for example, my videos Plant-Based Diet & Mood, Inflammatory Remarks About Arachidonic Acid, and Chicken, Eggs and Inflammation. Arachidonic acid is one of more than a thousand different topics I cover. If you haven't yet, you can subscribe to my videos for free by clicking here.
For more context, check out my associated blog posts: How To Boost Serotonin Naturally, Top 10 Most Popular Videos of the Year,Saffron vs. Prozac for Depression, and Treating Parkinson's Disease with Diet