How to Become Smarter (32 page)

Psychotropic drugs do not always have identical effects in humans and in laboratory rodents. For example, different classes of antidepressant drugs work differently in different animal models of depression [
448
]. Porsolt swim test, also known as the behavioral despair test, is an established experimental model of depression. It involves placing a rodent in a cylinder filled with water, from which the animal cannot escape, and measuring the time the animal spends without moving. The original Porsolt swim test was sensitive to the effects of older classes of antidepressant drugs such as tricyclics and MAOIs (monoamine oxidase inhibitors). But researchers had to modify this test later because it could not detect the antidepressant properties of SSRIs (selective serotonin reuptake inhibitors), the newer class of antidepressants [
448
]. In addition, SSRIs have a rapid antianxiety effect in rat models of anxiety, within hours [
449
]. In humans, they start to reduce anxiety only after 2 or 3 weeks of daily administration [
450
]. In summary, the mood-lowering effect of cooked meat may be due to the psychoactive properties of mutagens that form during cooking of muscle meats.

Note that the amount of mutagens in meat cooked at moderate temperatures is negligible, almost undetectable. Therefore, this kind of food does not pose any risks to health, although it may have subtle effects on mental state. We saw in Chapter One that low doses of chemicals often have effects that are different from the effects of high doses, the phenomenon known as hormesis.

Another chemical that may be responsible for the mood-lowering effect of cooked meat is creatinine. It plays a role in normal metabolic processes of the human body and is present at a low level in blood. Research shows that creatinine can be responsible for fatigue and low mood that may result from consumption of large amounts of cooked meat. The level of creatinine in meat increases over 30-fold during cooking [
130
]. A meal of uncooked meat has no effect on blood level of creatinine in humans [
130
], whereas a meal consisting of
cooked
meat raises the blood creatinine for several hours [
130
,
184
]. Elevated levels of creatinine in blood and insufficient elimination of creatinine from circulation by kidneys correlate with fatigue [
185
-
187
] and symptoms of depression in various groups of patients [
188
-
191
]. This association does not necessarily mean that creatinine causes fatigue and depression. Elevated blood creatinine is an indicator of kidney dysfunction, and it is possible that kidney dysfunction rather than creatinine itself is responsible for fatigue and symptoms of depression. This is because elimination of all kinds of waste (including creatinine) from circulation is impaired when kidneys are malfunctioning. Further research is needed to determine whether creatinine contributes to fatigue and symptoms of depression or if creatinine merely correlates with these problems. Elevated blood levels of creatinine also correlate with cognitive impairment in various groups of patients [
192
-
195
], but it is unknown if this relationship is causal or coincidental.

Large amounts of cooked meat do not worsen mood in the context of a low-carbohydrate diet, when the body switches to burning of fat instead of carbohydrates as a main source of energy. This metabolic state is called ketosis, and many low-carb diets are called ketogenic diets because they can induce ketosis [
451
]. Several studies show positive effects of ketogenic diets, such the Atkins diet, on mood [
277
], and my personal experience supports these results. In my experience, the Atkins diet (the induction phase) can worsen mood during the first few days but subsequently mood normalizes. Why does the Atkins diet not worsen mood, but a mixed diet that contains large amounts of cooked meat worsens mood? Maybe because during ketosis, the human body processes cooking mutagens in a different way.
^E

To summarize, creatinine, some polycyclic aromatic hydrocarbons, and heterocyclic amines may be responsible for the negative effects of cooked meat on mood. Yet hard evidence at realistic doses is lacking.

In my experience, another type of food that can lower mood is raw nuts, such as walnuts, filbert, or pecans. Several studies on laboratory animals show that nuts can cause malaise and symptoms of depression [
252
-
254
]. These findings do not imply that nuts should lower mood in humans, but my personal experience suggests that nuts do lower mood. If I consume them in large amounts daily, nuts can cause apathy, nausea, and headache. I have not been able to find a possible explanation for these effects of nuts. In addition, roasted nuts give me headache even if I consume them in small amounts (on a daily basis).

As for cooked grains, we saw in previous chapters that boiled whole grains have a mild sedative effect: they can slow you down and improve sleep. In contrast, my personal experience suggests that raw grains or raw water extract of grains do not have this sedative effect. We saw in Chapter Two that the sedative effect may be due to the small (safe) amounts of Maillard reaction products, such as acrylamide. These chemicals form during cooking of grains (Table 2). (Readers can skip the technical details by pressing the skip button or
this link
.) Acrylamide at high doses reduces the level of activity of laboratory animals and can impair short-term memory and learning [
231
-
233
]. Sedative drugs such as benzodiazepines and barbiturates have similar effects on the central nervous system. High doses of acrylamide (over 1 milligram per kilogram of body weight per day) are toxic to nerve cells and can cause neurological damage. The average exposure to acrylamide from food is hundreds of times lower [
220
]. This lower dose of acrylamide does not cause any detectable neurological damage in laboratory animals. These low levels of acrylamide may have subtle effects on mental abilities of humans, but scientists have yet to investigate this area.

Some foods, such as crispbread, potato chips, and French fries, contain significant amounts of acrylamide, but they cannot cause acrylamide poisoning even if consumed in large amounts on a regular basis (
Table 2
). Whole grains cooked at moderate temperatures contain undetectable levels of acrylamide and should not be a cause for alarm. Bread (high cooking temperature) contains detectable but low levels of acrylamide and it is unclear if this can cause negative effects on health in the long term (
Table 2
). The mild sedative effect of cooked grains may also be due to some other, yet unidentified compounds, which are unrelated to Maillard reaction products. In summary, cooked grains appear to cause a slowing of behavior, that is, a mild sedative effect. This may be due to Maillard reaction products or to some other chemicals that form during cooking of cereal grains.

It bears repeating that you should not be scared of the small amounts of mutagens and Maillard reaction products (e.g., acrylamide) that may be present in cooked meat and cooked grains. These low doses cannot cause detectable health problems in humans and laboratory animals. The detoxification system in the human liver can neutralize these small amounts of those chemicals. Don’t be scared of food cooked at moderate temperatures (by boiling or by steaming). Keep in mind that humans must have adapted to cooked food at least partially during the past 300,000 years of evolution. Meat and grains cooked at moderate temperatures are healthy foods and will not cause adverse effects on physical health in the context of a balanced diet. You will see later that the moderate lowering of mood and slowing can serve several useful functions.

The combination of the slowing with lowered mood resembles symptoms of clinical depression. Hence I named the diet that is based on boiled grains, boiled meat, and nuts the “
depressant diet
.” This diet also includes raw fruits and vegetables, but it excludes all dairy products. We saw in Chapter Three that adding significant amounts of dairy to the diet can reverse the low mood and apathy that result from consumption of large amounts of cooked meat. The mechanism underlying this beneficial effect of dairy is unknown. It is possible that milk may somehow facilitate neutralization of mutagens by the liver detoxification system.
^E

The detailed composition of the depressant diet is as follows (proportions by weight):

• boiled or steamed whole-grain cereals (25-35%),
  
• boiled or steamed meat such as ground beef or chicken (40-50%),
  
• nuts (2-5%),
  
• raw fruits and vegetables (20-23%).
  

The recommended proportion of red meat (beef, pork, or mutton) is at least one half of all meat; the rest can be poultry such as chicken or turkey. This diet does not allow any dairy products. Most of the fruits and vegetables should be raw. You can drink water in any amounts. If you use this diet for 2-3 days, the most noticeable effects are slight apathy, lowered mood, the feeling of being slowed down, fatigue or drowsiness, and increased emotional tension or mild anxiety. If the diet excludes all artificial ingredients, then it will not worsen mental abilities, i.e. it will not impair judgment. But it will not improve mental abilities either. The composition of the depressant diet as described above cannot cause clinically depressed mood even if you use this diet for a month or longer. But low mood or apathy of tolerable intensity are likely. You may also start feeling stressed out. Sometimes, this diet may elevate mood during the first one or two days, but afterwards it lowers mood, increases sleep, and reduces activity, based on my experience. This diet improves sleep as effectively as the grains-only diet (Chapter Two).

We can modify the depressant diet such that it excludes all grains, while cooked red meat is the only source of animal protein. This version of the diet can cause significantly depressed mood within one or two weeks. This diet, however, has little or no sedative effect. This “harsh” version of the depressant diet consists of:

• cooked red meat such as pork, beef, or mutton (50% by weight),
  
• nuts (5-10%),
  
• fruits and vegetables (40-45% by weight).
  

It is important to exclude all dairy from this diet. The amount of fruits and vegetables should be sufficient to prevent ketosis. This harsh version of the depressant diet does not improve sleep and may cause nightmares if you use it long enough. The person may also start feeling stressed. The harsh depressant diet, in my view, may serve as an experimental model of depression, and it is possible to test this diet in controlled studies. If meat contains sufficient amounts of fat and is cooked at moderate temperatures, then the person may feel well physically but will feel bad
mentally
. On the other hand, if meat is lean and cooked at high temperatures, then the volunteer will feel bad
both
physically
and
mentally. This will not be a good experimental model of a mental disorder.

Granted, the harsh version of the depressant diet, even when it lasts for several months, may cause only mild (yet clinically significant) depression. Nonetheless, this experimental model seems to predispose a person to severe depression—a negative life event can serve as a trigger. Thus, in order for severe depression to occur, it seems that there are two necessary conditions: biological predisposition and a negative life event. I went through all of this myself in the late 1990s, when I was using this high-protein diet for extended periods of time. At one point, I became suicidal and was able to recover from the severe depression only when I abandoned this deficient diet. This negative experience is what prompted my interest in experiments with raw animal food. (Readers should not follow my bad example in this case.)

Going back to the first version of the depressant diet (the milder one, containing cooked grains), it has some beneficial effects. These effects include a tendency to think things through before doing anything (low impulsivity); an ability to suppress almost any urge or impulse; improved sleep and maybe an increased amount of sleep. We will discuss the ways of reducing impulsivity in more detail at the end of Chapter Six. This diet also reduces procrastination, as you will see in the next chapter. This diet is not a “smart diet” because it causes substantial slowing (for example, in social interactions) and it is not useful for solving complex problems.

In theory, the depressant diet should be beneficial for patients with bipolar disorder during manic and hypomanic episodes. Nobody has tested this idea in clinical trials. (I have never had a diagnosis of bipolar disorder, although I
have
had undiagnosed episodes of depression and artificial hypomania.) In my experience, whole-grain bread has stronger sedative properties compared to boiled grains. Therefore, a depressant diet containing large amounts of whole-grain bread should be more effective during manic episodes. Researchers who wish to test the effectiveness of this diet in bipolar patients can use a study protocol similar to the one described in
endnote L
. If somebody conducts clinical trials and finds this diet to be effective in mania, then patients can probably use it in combination with other treatments. This is because the diet should be compatible with medication and other therapies. (In contrast, a hot environment should also be effective in mania, but it is not compatible with sedative and neuroleptic drugs.) Based on my experience, possible side effects of the depressant diet are the following. This diet may cause a feeling of being stressed out; it can increase apathy and boredom; after several months, this diet can cause a small weight gain. Rare side effects include mild headache. On the positive side, the depressant diet does not impair judgment.