Discussions of how a meat-based diet made us smart by spurring human evolution usually center around meat providing concentrated calories or essential fatty acids. This new research suggests that the creatine provided by meat also supports better cognitive function among carnivores compared to vegetarians.
According to the abstract of the BJN article:
Young adult females (n 128) were separated into those who were and were not vegetarian. Randomly and under a double-blind procedure, subjects consumed either a placebo or 20 g of creatine supplement for 5 d. Creatine supplementation did not influence measures of verbal fluency and vigilance. However, in vegetarians rather than in those who consume meat, creatine supplementation resulted in better memory. Irrespective of dietary style, the supplementation of creatine decreased the variability in the responses to a choice reaction-time task.Memory is essential to learning, so we can conclude that a vegetarian supplemented with creatine will learn better than the same vegetarian not supplemented. But why not just eat meat, an excellent dietary source of creatine? As Wikipedia points out:
In humans and animals, approximately half of stored creatine originates from food (mainly from meat). Since vegetables do not contain creatine, vegetarians show lower levels of muscle creatine, but show the same levels after using supplements.So, take a creatine-depleted vegetarian, feed him/her some meat, and voila, now you have a smarter animal. I have some experience with this. All my life I have had an exceptionally good memory, so long as I ate meat; but during the time I spent trying to make a vegetarian diet support my health, I had a significant decline in ability to memorize and recall information, obvious not only to me but to people close to me.
One author reported on this study using the title "Creatine may beef up brain function" in an online journal focusing on supplements. Apt, but I'd rather see people beef up brain function by eating real food: beef!
Vegetarians will likely protest that the Institute of Medicine (IOM) does not presently classify creatine as an essential nutrient because human cells can manufacture it from the amino acids arginine, glycine, and methionine. However, the IOM's failure to classify a nutrient as essential fact does NOT mean that the nutrient is not essential.
The history of choline illustrates these points further. Adolf Strecker discovered choline, a water-soluble nutrient often grouped with B-vitamins, in 1864. Mammals manufacture some choline using S-adenosylmethionine, derived from the amino acid methionine, as a raw material. Because of endogenous synthesis, the Institute of Medicine did not classify choline among the essential nutrients until 1998.
Choline is another nutrient better supplied by meat and especially eggs than by plant foods, and the Wikipedia entry on choline includes this bit:
Strict vegetarians who avoid all animal products, endurance athletes and people who drink a lot of alcohol may be at risk for choline deficiency and may benefit from choline supplements.
In general, people who do not eat many whole eggs may have to pay close attention to get enough choline in their diets. Studies on a number of different populations have found that the average intake of choline was below the Adequate Intake (AI).The body needs choline to manufacture acetylcholine, the primary neurotransmitter, and choline is required for full development of the central nervous system, particularly the memory center of the brain.
Choline deficiency during fetal development affects memory profoundly throughout life. In Choline: Critical Role During Fetal Development and Dietary Requirements in Adults Steven Zeisel reports on animal studies of choline deficiency:
Mothers fed choline-deficient diets during late pregnancy have offspring with diminished progenitor cell proliferation and increased apoptosis in fetal hippocampus....and decremented visuospatial and auditory memory.In contrast, Zeisel reports that although adult rodents decrement in memory as they age, offspring exposed to extra choline in utero do not show this “senility.”
Zeisel also reports on results of studies of choline supplementation in humans. Among the findings:
In a double-blind study using normal college students, 25 g of phosphatidylcholine caused significant improvement in explicit memory, as measured by a serial learning task; this improvement might have been due to the improved responses of slow learners. A single oral 10 g dose of choline chloride given to normal volunteers significantly decreased the number of trials needed to master a serial-learning word test. The precursor for formation of phosphatidylcholine, cytidine diphosphocholine (CDP-choline), also has been tested for memory-enhancing effects. In a randomized, double-blind, placebo-controlled study, volunteers were treated with 1000 mg/d CDP-choline or placebo for three months. CDP-choline improved immediate and delayed logical memory. In a second study, oral administration of CDP-choline (500−1000 mg/day) for four weeks to elderly subjects with memory deficits but without dementia resulted in improved memory in free recall tasks, but not in recognition tests. In a double-blind study, patients with early Alzheimer-type dementia were treated with 25 g/day phosphatidylcholine for six months. Modest improvements were observed compared with placebo in several memory tests. However, there are studies in which the choline effect on memory was not observed in normal subjects or in patients with dementias.
Given the rather poor track record of supplements, and the fact that humans are evolutionarily adapted to food, not isolated nutrients, I wonder what results these studies would have gotten if instead of using isolated choline chloride or phosphatydylcholine they had simply advised the subjects to eat 3-6 eggs and more than 8 ounces of meat daily.
Stephan blogged about research showing that choline also prevents and reverses non-alcoholic fatty liver disease even in the context of high sugar intake. Eat egg yolks for a healthy brain and a healthy liver.
These types of findings indicate that humans have long ago adapted to and become dependent upon meat. If humans did not need meat, they would have the ability to synthesize optimum amounts of creatine and choline in the absence of dietary meat. Chances are, dietary creatine is as essential to human health as choline or vitamin B-12.
History suggests we might wait perhaps a century for the Institute of Medicine to decide that creatine is an essential nutrient. Meanwhile, we have enough evidence: Humans need meat for optimum health of the nervous system, and the anthropological and experimental evidence already indicates eating meat can literally make you "smarter" than if you don't eat meat.