How to Become Smarter (8 page)

1. Dietary fiber supplements are a special category of nutritional supplements that are
   indigestible
   by humans. Therefore, people can use these supplements without any fear that they may adversely affect mental state. These include micro-crystal cellulose, psyllium husks, and other indigestible types of dietary fiber (be careful with
   digestible
   types of fiber, such as apple pectin). In your alimentary tract, the action of indigestible fiber is purely mechanical (propulsion and lubrication). Fiber supplements are useful in the context of high-protein diets, as we will see in subsequent chapters. You could say that fiber supplements such as psyllium husks and water extract of raw wheat are “natural” rather than artificial components of the diet. This is because people prepare them by means of a simple mechanical process.
   
2. The natural intelligence theory ignores stuff applied to the body externally, such as balms, cosmetics, antiperspirants, and the like, and household chemicals, such as air-fresheners. If you use these products as instructed by the manufacturer, they will not affect either mental state or mental abilities.
   

The natural intelligence theory has several implications. First, complete exclusion of all artificial ingredients from the diet (with some of the above exceptions) is safe and feasible and will improve intelligence, according to this theory. Second, food that is cooked at moderate temperatures (e.g., by boiling or steaming) will be more beneficial for mental abilities than food cooked at high temperatures (for example, by frying, baking, or grilling). This is because the high temperature treatments cause greater changes in the chemical composition of food, making it less “natural,” as it were.

If the natural intelligence theory has any validity, there should be evidence that cooking of food and the presence of artificial ingredients in the diet can worsen mental abilities. The next two sections review this evidence.

• From the standpoint of evolution, the human brain may not be adapted to a modern diet that is mostly cooked, highly processed, and chockfull of artificial ingredients because this diet is a recent innovation.
  
• The diet of modern primates in the wild and that of the evolutionary predecessors of humans (roughly 300,000 years ago) is a raw food diet free of artificial ingredients (refined sugar, vinegar, nitrates, and others). This diet can be considered a natural diet of primates or an ancestral diet of humans. It is unclear what the “natural diet” of modern humans is.
  
• The natural intelligence theory suggests that it is possible to improve mental clarity by means of the ancestral diet or by means of a safe diet similar in its composition to the ancestral diet.
  
• There are several limitations of the natural intelligence theory: consumption of uncooked animal products poses a risk of serious infectious diseases for modern humans and may worsen mental abilities due to deterioration of the general state of health; the natural intelligence theory is not the same as naturopathy or natural medicine; prescription drugs do not worsen intelligence, but refusal of treatment can; the distinction between “natural” and “unnatural” food is arbitrary; there are some differences with the theory behind the Paleolithic diet; strict diets can cause problems in social relations; to improve mental abilities, people don’t need to use strict diets on a permanent basis; cooking destroys toxic substances in some plant foods; fluoridation of water is not harmful; adding small amounts of table salt to food will not impair mental abilities; genetically modified food and food that is not organic can be considered “natural.”
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Let me clarify the meaning of the term “artificial ingredients.” The word “artificial” means in this context that humans used a sophisticated chemical process to create these ingredients. For example, sugar beets may be a man’s doing, but they do not undergo a sophisticated chemical process. Therefore, sugar beets are not an artificial ingredient. On the other hand, refined sugar is an artificial ingredient. Many of these artificial ingredients are pure chemicals and can be called “food additives.” This book uses the terms “artificial ingredients” and “food additives” interchangeably. Dietary supplements such as artificial vitamins and minerals are also in the category of artificial ingredients. Vitamins and minerals are often called “micronutrients” in order to distinguish them from macronutrients (carbohydrates, fat, and protein).

There is a long list of food additives (several hundred) that the health authorities have approved as safe to add to food in small amounts. This includes categories of chemicals such as acidity regulators, anti-caking agents, anti-foaming agents, antioxidants, color retention agents, emulsifiers, firming agents, flavor enhancers, flour treatment agents, food acids, food coloring, gelling agents, glazing agents, humectants, improving agents, mineral salts, preservatives, propellants, seasonings, sequestrants, stabilizers, sweeteners, thickeners, and vegetable gums. The additives that are most familiar are refined sugar (sucrose) and table salt (sodium chloride). You can find an up-to-date list of the artificial ingredients in the Wikipedia article entitled “List of food additives.”

Food additives do not have adverse effects on physical health at doses present in food products that you find in a grocery store. For this reason, regulatory agencies, such as the United States Food and Drug Administration, have approved these chemicals as safe for use in food products. Nonetheless, many food additives can have subtle effects on the functioning of the central nervous system
^G
in laboratory animals and in humans, as discussed below. (Readers can skip the detailed discussion of this topic and jump to the key points: press the skip button or
this link
.)

Before discussing the effects of food additives on mental abilities, I should say that readers need to view the results of the studies below with caution for two reasons. The first reason is that the dose of a given food additive in animal studies is not always equivalent to the dose that an average human receives with food. The second reason is that the physiology of laboratory animals, most often rodents, is not identical to human physiology. Therefore, research findings of adverse effects of a given chemical in rats are not always applicable to humans, although, usually, they
are
applicable to humans. It is not my purpose here to scare the reader into adhering to some diets by fear-mongering and exaggerating undesirable effects of food additives. Rather, this text is trying to make a point that a
temporary
elimination of food additives from the diet should improve mental abilities. But if you choose not to follow my advice and continue to consume food additives as usual, you are not going to become stupid or mentally ill. The research into the effects of food additives on mental state remains controversial, and you need to be careful when interpreting the results of such studies.

One of the pioneers of the research into the effects of food additives on human behavior was Dr. Benjamin Feingold, whose main area of expertise was allergies in children. In his clinical practice in the 1960s, he noticed that elimination of some food additives from the diet of children can not only reduce allergic reactions but also improve the behavior of some children. His initial studies were promising and he advanced the “Feingold hypothesis.” This theory suggests that some food additives such as food coloring agents, artificial flavors, some preservatives (BHA, BHT, TBHQ), and aspartame can cause hyperactivity in children. This hyperactivity is known today as attention deficit hyperactivity disorder, ADHD. Subsequent studies by others, who tried to reproduce the findings of Dr. Feingold’s research team, failed to support the hypothesis. (The Feingold diet did show some improvements in other components of child behavior.) The Feingold diet showed benefits in open experiments, where the participants or those recording the results knew whether a patient received the active treatment or the control treatment. This diet, however, provided little or no benefit to children with ADHD in
blinded
clinical trials. In those studies, the participants or those recording the results did not know whether a patient received the active or the placebo treatment. Put another way, we can attribute most of the initially reported benefits of the Feingold diet to the placebo effect and the observer bias. Studies of children on the Feingold diet, where scientists added one of the food additives back to the diet, failed to show negative behavioral changes in response to the suspected chemicals. Nevertheless, more recent studies, where researchers added a cocktail of several food additives to the diet, did show that food additives can contribute to hyperactive behavior in children [
62
,
63
]. These were rigorous studies known as randomized controlled trials, and many of them were double-blind randomized controlled trials. The latter are “the golden standard” of clinical research.

For example, one study shows that a cocktail of several food additives, when ingested at realistic doses, contributes to inattentive/hyperactive behavior in children [
63
]. They tested two different cocktails: one contained approximately 70 mg daily of the mixture of sunset yellow, carmoisine, tartrazine, ponceau 4R, and sodium benzoate. The second cocktail contained approximately 110 mg daily of the mixture of sunset yellow, carmoisine, quinoline yellow, allura red AC, and sodium benzoate. The amounts of each cocktail were smaller for 3-year-olds. This was a double-blind randomized placebo-controlled study that included approximately 270 children total. The authors concluded that a mixture of food additives commonly present in food can increase symptoms of inattention/hyperactivity in children. The finding was statistically significant, but the magnitude of the negative effect of food additives was modest. The observed modest effect cannot account for the large difference in symptoms between healthy children and children with attention deficit hyperactivity disorder [
63
]. An earlier study by the same group of researchers reached similar conclusions [
62
]. In 2004, a review of studies of the effects of food additives on hyperactivity in children identified 8 high-quality, well-designed clinical trials. That review reached the same conclusions: a) food additives have a noticeable, statistically significant effect in that they increase hyperactivity/inattention in children; b) the magnitude of the effect is small and cannot explain the symptoms of children diagnosed with ADHD [
64
].

Recent studies of “elimination diets” or “a few foods diet” show that these diets can work as a treatment for attention deficit hyperactivity disorder [
65
-
67
]. These diets exclude all food additives and consist of a small number of food products that rarely cause food allergies. (The Feingold diet eliminates some but not all food additives and imposes fewer restrictions on food products.) One study investigated effects of an elimination diet consisting of rice, turkey, lamb, vegetables, fruits, margarine, vegetable oil, tea, pear juice, and water [
67
]. Seventy percent of children with ADHD showed significant improvements on this diet. This magnitude of effectiveness is comparable to the effectiveness of ADHD drugs. The control group did not follow any particular diet and thus was a no-treatment control.

This and earlier similar clinical trials were “open” studies, where test subjects and people assessing the symptoms (parents and teachers) knew which children were in the control and the experimental groups. Therefore, there is a chance that the results of this study contain a bias. For example, if some parents or teachers opposed the widespread pharmacological treatment of ADHD, they could inadvertently make the effects of the elimination diet look better than they were. As we saw in an earlier section of this chapter, it is possible to eliminate this bias. One option is to design a control diet and to conduct a blinded clinical trial where participants do not know which diet is supposed to have therapeutic effects. Another option is to compare the elimination diet with a drug known to be better than a placebo in ADHD patients. Open trials of diets that Benjamin Feingold conducted four decades earlier showed promising results, but later, blinded clinical trials by other investigators failed to confirm those results. Nonetheless, in principle, the results from clinical trials of elimination diets are in agreement with the recent rigorous studies of mixtures of food additives that we reviewed in the previous paragraph.

There are some studies that investigated possible benefits of elimination diets in autism, a brain disorder in the category of pervasive developmental disorders. The main symptom of autism is impaired social interaction, among other problems. A review of these reports concluded that the quality of these clinical trials was inadequate and further research is needed to obtain conclusive results [
68
].

Still other studies have investigated the effects of individual food additives on healthy humans and laboratory animals. Many of these chemicals are different from the additives that were the focus of Benjamin Feingold’s research. These other studies show that some food additives can impair learning, memory, alertness, or activity level. The list of the artificial ingredients that may have undesirable effects on mental state includes erythrosine, iron, leucine, magnesium sulfate, monosodium glutamate, nitrates, nitrites, propionic acid, propylene glycol, refined sugar (sucrose), and stannous chloride. Some of the studies below used the amounts of food additives that are comparable to the amounts that modern humans ingest with food. In this case, the evidence suggests that those additives can have undesirable effects on humans. Most of the studies discussed below used the amounts of a given food additive that far exceed the dose that a modern human being normally ingests with food. These studies fail to prove that food products containing those additives have undesirable effects on mental health. Yet these studies do show that, in principle, pure chemicals (artificial ingredients) can cause detrimental consequences when ingested in large amounts. In other words, this research shows that “unnatural” or unusual types of food, such as large amounts of a pure chemical, can have negative effects on functioning of the brain. (Note that many species of plants and mushrooms are poisonous to humans and thus also represent “unnatural” food.)