Prior to the advent of prozac and SSRIs (selective serotonin reuptake inhibitors) there was l-tryptophan, or tryptophan, the runt of the amino acid world. While some claim that no one is protein deficient, that we don't die from lack of protein, it was a series of health issues resulting from inadequate protein consumption seen at the turn of the century that ignited research into this area and led to the discovery of tryptophan in 1901. From my experience in practice and that of other professionals, I can tell you that inadequate protein is an issue that comes up with alarming frequency. This doesn't mean you need to start digging into 8oz rib-eyes on the regular, but it's important to be mindful of consumption and to incorporate a concentrated source at least twice daily (more if you're active or looking to add lean mass.)
Supplementation of l-tryptophan was considered wildly successful until the 1980s, when Japanese manufacturer Showa Denko prepared a bad batch containing impurities. Roughly 5,000 people developed eosinophilia myalgia syndrome, an incurable and often fatal flu-like neurological condition. Tryptophan was subsequently banned and discredited, something that's just beginning to shift.
Tryptophan converts into something called 5-HTP, which then converts into serotonin (provided everything is in fine working order). It's associated with mood, memory, and sociability, as well as feelings of calm and relaxation. Unfortunately, it's the least abundant amino acid and competes with all of the other amino acids to cross the blood brain barrier. When it has to fight with all of the other guys, like methionine, it gets left behind and abandoned.
My experience with ketosis and subsequent insomnia convinced me that very low-carbohydrate and high-fat diets are not the answer for depression (and certainly not for those with thyroid issues). Some probably do experience relief from their symptoms, but I suspect it has more to do with lower protein intake. To stay in ketosis you can't consume excessive amounts of protein, for the liver will convert any extra into glucose and burn that instead of fat. But isn't the answer to low tryptophan more protein? That's where the Tryptophan Paradox emerges. Because tryptophan competes for absorption and doesn't exist in isolation, the more protein you consume, the less of it you're likely to get. Which means excessive protein consumption, particularly from foods that contain all 9 essential amino acids (animal foods, hemp seeds, protein powders), can further deplete tryptophan stores. Ketosis, done right, is actually quite high in plant foods, which contain some protein (amino acids) but are incomplete sources - less competition for our darling tryp. So on one hand, yes, it's possible some will experience relief from their symptoms, but they may not have had to go to such extremes to do so. It's not just the consumption of fat, protein and carbohydrate that matters - sources and timing mean something, too.
As a side note, there's definitely a link between vegetarianism and eating disorders, something I suspected and that was confirmed several months ago by Dr. James Greenblatt. Our bodies are ridiculously amazing and endlessly fascinating, and if my experience in ketosis taught me anything, it's that they will ask for exactly what they need if we listen. Some individuals, particularly women, turned off by meat for whatever reason, convert to vegetarianism during their adolescent years. We see some negative manifestations of this - those who become carbavores, deplete their bodies of nutrients, and consequently develop an assortment of health issues (not to simplify things, but such as eating disorders). We also see positive recovery stories - Angela Liddon at Oh She Glows, Gena Hamshaw at Choosing Raw, Leanne Vogel at Healthful Pursuit (she was vegan, though she eats meat now). While I don't have any studies to cite, I wonder if those who battle with eating disorders have inherited a genetic predisposition to under-produce serotonin (a real thing), and find greater peace and happiness while on a plant-based diet because they're better able to absorb tryptophan.
Secondly, light impacts the conversion of tryptophan. During the day, tryptophan converts into serotonin and keeps us calm. At night, in the absence of light, it converts into melatonin and helps us to sleep. It's so crucial that we dim the lights and shut off electronics (ideally) after dinner or a few hours before sleep. If you have trouble sleeping, eating a vegetarian dinner with some carbohydrate (which spikes insulin and will divert the other amino acids into the muscles) and following the above advice can really help. I also like taking a product called Natural Calm (magnesium citrate), which tends to relax the muscles and relieve anxiety. We've long been advised to eat carbs during the day, but concentrated forms should really be left to the evening because they promote a restful sleep. Of course, if you're very active and require many carbohydrates, or workout in the morning, you'll need to refeed accordingly. In contrast, high protein meals can energize us because they raise tyrosine levels - hello dopamine and norepinephrine! These high protein meals can help boost thyroid hormone production, which in turn, yes, boosts or optimizes metabolism. A diet too low in protein can result in two things: thyroid hormone production decreases (promoting weight gain, since metabolism slows) and carbohydrates are eaten instead (again, promoting weight gain.) I'm not attacking carbs; this has less to do with carbohydrate as an entity and more to do with too much carbohydrate.
If you suffer from depression, sleep, anxiety, obsessive-compulsive disorder, disordered eating, the blahs/general dissatisfaction, poor mood, or low self-esteem, here's some suggestions on how to boost trytophan intake:
- Eat legumes: lentil and bean soups, lentil and bean salads, vegetarian chili and stews, sweet potato stuffed with black beans or pinto beans, curries, pinto bean tacos/burritos, etc. Brown rice and sesame seeds/tahini are great sources.
- Consume plenty of vegetables, required for proper brain function (broccoli and mushrooms are somewhat higher in incomplete protein, too);
- Make sure you're getting plenty of healthy fats (broken record, but it's true);
Eat a vegetarian meal at night, at least some of the time;
- Eat carbohydrate, ideally starchy root vegetables or rice, with concentrated forms of protein (chicken, turkey, fish, etc.);
- Take a B-complex in the morning, particularly if you lead a stressful lifestyle or take the birth control pill, which depletes Bs;
- Dim the lights in the evening and put. the. phone. away.;
- Try reading before bed instead of watching television or a movie (definitely don't watch violent/scary films before bed, which have been shown to raise cortisol production and promote stress);
- Consider sipping on a glass of Natural Calm. Most people are deficient in magnesium. I like the raspberry lemon flavour with the juice of 1/2 a lemon for a sugar-free riff on pink lemonade, especially nice during the warmer months.