Calcium is the most abundant mineral in the human body, and although 99 percent of your body’s calcium is stored in the bones, the remaining 1 percent is found in the blood and within cells, where it performs a vital role in dozens of metabolic processes. Research into the effects of calcium on metabolism has revealed the profound impact of calcium in such areas as reducing the risk of colon cancer, cutting symptoms of PMS in half (pain, bloating, mood swings, and food cravings), and controlling blood pressure. If this weren’t enough evidence that calcium supplements might be a good idea, there is also some evidence that calcium can even influence mood and behavior. This possibility comes from studies of rats, in which the animals become agitated when fed a low-calcium diet but are more calm and relaxed when their diets contain adequate calcium levels.
You may have noticed the "Got Milk?" advertising campaign in recent years, produced by the National Dairy Council. The obvious purpose of the ads is to convince you to drink more milk and consume more dairy products in general (not a bad idea for most people). Some of these ads depict potential weight-loss benefits from getting your full daily dose of calcium—and the research to support this position has come from several universities across the country. Scientists at the University of Tennessee have found that low calcium intake is associated with elevated cortisol production within fat cells. As I discussed in Chapter 4, if you’re trying to lose weight, the last thing you want is to develop high levels of cortisol within your fat cells, because it is precisely this cortisol that serves as a potent "fat-storing" signal, especially to the fat cells in your belly region.
Right now you may be thinking, "I already need calcium for strong bones, so I might as well get some more in my diet, just in case it really can help with weight control." To that, I’d say, "Great idea!"—and so would researchers from the University of Colorado, Purdue University, and Creighton University. Research from the University of Colorado has shown that subjects with the highest dietary calcium intake (whether from dairy products or calcium supplements) also had the highest calorie expenditure and fat metabolism. Purdue researchers found that the difference between consuming 1,000 mg/day of calcium versus 500 mg/day was as much as twenty pounds of body fat in two years (higher calcium intake leading to lower body fat levels). If all this weren’t enough, one of the world’s foremost calcium and bone metabolism experts, Dr. Robert Heaney, at Creighton University, in Nebraska, declared in a nutrition journal editorial that simply increasing calcium intake to 1,000–1,500 mg/day could reduce obesity in the population by 60 to 80 percent!
As a dietary supplement, calcium is about as safe as it gets, with side effects being quite rare and modest in severity (occasional constipation at higher intakes). Because practically nobody consumes enough calcium in their daily diet, and with calcium being so cheap and easily available, this is certainly one of the nutrients for which supplementation is most highly recommended.
Magnesium is a mineral that functions as a coenzyme (the active part of an enzyme system) for nerve and muscle function, regulation of body temperature, energy metabolism, DNA and RNA synthesis, and the formation of bones. The majority of the body’s magnesium (60 percent) is found in the bones; therefore, many of us tend to think of magnesium as a bone-specific nutrient.
Because magnesium serves as a cofactor for so many regulatory enzymes, particularly those involved with energy metabolism and nervous-system function, magnesium needs may increase during periods of heightened stress. Magnesium is required for proper enzyme function in converting carbohydrates, protein, and fat into energy—and at least a few studies have suggested a potential role for magnesium supplements in energy metabolism by showing increased exercise efficiency in endurance athletes. Although there is no overwhelming evidence to suggest any increases in muscular strength or elevated energy levels following magnesium supplementation, clinical studies have shown that magnesium supplements help lessen feelings of anxiety and overall stress.
The Daily Value (DV, another term for RDA) for magnesium is 400 mg per day, but requirements may be elevated somewhat by stressors such as exercise. Additionally, because magnesium increases calcium absorption, it is recommended that calcium supplements taken for bone building or prevention of bone loss contain magnesium. Food sources of magnesium include artichokes, nuts, beans, whole grains, and shellfish, but since nearly three-quarters of the American population fails to consume enough magnesium, supplements may be warranted—especially during periods of heightened stress. Excessive magnesium intake can cause diarrhea and general gastrointestinal distress, as well as interfere with calcium absorption and bone metabolism (even though optimal levels of magnesium assist calcium absorption). Therefore, since no known benefits are associated with consuming more than 600 mg per day of magnesium, higher intakes should be avoided.
Thiamin, also known as vitamin B-1, is a water-soluble vitamin that functions in carbohydrate metabolism to help convert pyruvate to acetyl CoA for entry into the Krebs cycle and subsequent steps to generate ATP. All this is technical talk for saying that thiamin helps give you energy. Thiamin also functions in maintaining the health of the nervous system and heart muscle. Food sources of thiamin include nuts, liver, brewer’s yeast, and pork.
Because of thiamin’s role in carbohydrate metabolism and nerve function, supplements have been promoted for increasing energy levels and maintaining memory. Thiamin also seems to be involved in the release of the neurotransmitter acetylcholine from nerve cells, and thiamin deficiency is associated with generalized muscle weakness and mental confusion.
Dietary thiamin requirements are based on caloric intake, so individuals who consume more calories, such as athletes, are likely to require a higher than average intake of thiamin to help process the extra carbohydrates into energy. During acute periods of stress, thiamin needs may be temporarily elevated, but outright thiamin deficiencies are rare except in individuals consuming a severely restricted diet.
No adverse side effects are known with thiamin intakes at RDA levels or even at levels several times the RDA, which is 1.5 mg. Virtually every multivitamin contains thiamin at 100 percent RDA levels or higher, with supplements focused on alleviating stress containing two to ten times RDA levels, dosages that are still quite safe.
Riboflavin, also known as vitamin B-2, is a water-soluble vitamin that serves primarily as a coenzyme for many metabolic processes in the body, such as formation of red blood cells and function of the nervous system. Riboflavin is involved in energy production as part of the electron transport chain that produces cellular energy. As a building block for FAD (flavin adenine dinucleotide), riboflavin is a crucial component in converting food into energy. FAD is required for electron transport and ATP production in the Krebs cycle. Liver, dairy products, dark-green vegetables, and many seafoods are good sources of riboflavin.
Requirements for riboflavin, like most B vitamins, are related to calorie intake—so the more food you eat, the more riboflavin you need to support the metabolic processes that will convert the food into usable energy (but by eating the right foods, such as dairy products and veggies, you’ll also be getting more riboflavin). Women should be aware that riboflavin needs are elevated during pregnancy and lactation, as well as when taking oral contraceptives (birth-control pills). Athletes may require more riboflavin due to both increased caloric intake and increased energy needs induced by exercise, which the body perceives as a stressor.
There is no strong support for the efficacy of isolated riboflavin supplements in promoting health outside of correcting a nutrient deficiency. Despite the role of riboflavin in a variety of energy-generating processes, the chances of a supplement improving energy levels in a well-nourished person is unlikely, but those individuals under high levels of emotional or physical stress may have increased requirements.
No serious side effects have been reported for supplementation with riboflavin at levels several times above the DV of 1.7 mg. Because the body excretes excess riboflavin in the urine, high supplemental levels are likely to result in fluorescent-yellow urine.
Pantothenic acid, also known as vitamin B-5, is a water-soluble vitamin widely distributed in most animal and plant foods. It is physiologically active as part of two coenzymes: acetyl coenzyme A (CoA) and acyl carrier protein. Pantothenic acid functions in the oxidation of fatty acids and carbohydrates for energy production, as well as in the synthesis of fatty acids, ketones, cholesterol, phospholipids, steroid hormones, and amino acids. Food sources of pantothenic acid include liver, egg yolk, fresh vegetables, legumes, yeast, and whole grains. Because it is found in many foods, a deficiency is extremely rare in people who consume a varied diet.
Vitamin B-5 is often referred to as an "antistress" vitamin because of its central role in adrenal-cortex function and cellular metabolism. Unfortunately, there is limited evidence from controlled studies to suggest that pantothenic acid taken on its own will reduce feelings of stress and anxiety or provide protection during times of stress. Therefore, it probably makes more sense to consume vitamin B-5, along with the other B-complex vitamins, as part of a balanced blend of all the essential nutrients, because there is good cortisol-control data for mixtures of B vitamins that include B-5.
As a water-soluble B vitamin, B-5 is generally considered a safe supplement, but large doses (10 grams or more) may cause diarrhea. Additional supplementation beyond the levels found in a multivitamin blend (5–50 mg per day) is probably unnecessary.
Pyridoxine, also known as vitamin B-6, is a water-soluble vitamin that performs as a cofactor for about seventy different enzyme systems, most of which have something to do with amino acid and protein metabolism. Because vitamin B-6 is also involved in the synthesis of neurotransmitters in the brain and nerve cells, it is frequently recommended as a nutrient to support mental function (mood) and nerve conduction, especially during periods of heightened stress. Some athletic supplements include vitamin B-6 because of its role in the conversion of glycogen to glucose for energy in muscle tissue. Food sources of pyridoxine include poultry, fish, whole grains, and bananas.
Because vitamin B-6, like most of the B vitamins, is involved as a cofactor in such a wide variety of enzyme systems, claims can be made for virtually any health condition. For example, because B-6 is needed for the conversion of the amino acid tryptophan into niacin, a common B-6 claim relates to healthy cholesterol levels, because niacin can help lower cholesterol in some people. Because B-6 also plays a role in prostaglandin synthesis, claims are often made for B-6 in regulating blood pressure, heart function, and pain levels, each of which is partially regulated by prostaglandins. Vitamin B-6 needs are increased in individuals consuming a high-protein diet, as well as in women taking oral contraceptives (birth-control pills).
Vitamin B-6 supplements, in conjunction with folic acid, have been shown to have a significant effect in reducing plasma levels of homocysteine (an amino acid metabolite linked to increased risk of atherosclerosis). In many animal models of hypertension, supplemental pyridoxine lowers blood pressure, and there is preliminary evidence for antihypertensive activity in humans as well. Additionally, we know that physiological levels of pyridoxal phosphate (PLP, the active form of B-6) interact with glucocorticoid (cortisol) receptors to down-regulate their activity—suggesting that B-6 supplements may be able to favorably counteract some of the adverse effects of elevated cortisol levels.
Numerous animal studies have shown that animals subjected to various stressors have an increased incidence of gastric ulcers. Animals supplemented with pyridoxine tend to have fewer stress-induced ulcers compared to animals given placebo. In one notable study of rabbits exposed to hypoxic stress (resulting from high altitude and reduced oxygen levels), pyridoxine feeding was shown to reduce plasma levels of cortisol by as much as 55 percent.
As a water-soluble B vitamin, pyridoxine is generally very safe as a dietary supplement. Excessive intakes (2–6 grams acutely or 500 mg chronically) are associated with sensory neuropathy (loss of feeling in the extremities), which may or may not be reversible. The RDA for vitamin B-6 is only 2 mg per day, an amount contained in virtually all multivitamin supplements. Pregnant and lactating women should not take more than 100 mg of vitamin B-6 per day.
Summary: Vitamins and Minerals
When it comes to dietary supplementation for stress adaptation and cortisol control, the first line of defense appears in the form of a comprehensive multivitamin/multimineral supplement (MVMS). The most effective choices will be those products that offer a balanced blend of the key vitamins and minerals the body needs during the stress response. In particular, vitamin C, magnesium, and the full B-complex group are probably most important from the standpoint of their direct involvement in the body’s stress response, but all of the essential and semiessential vitamins and trace minerals are needed as well. A comprehensive MVMS, when used as part of a regimen of balanced diet and regular exercise, represents the antistress foundation on which you can add the targeted cortisol-control supplements that are covered in sections to come.