by Jason Fung
A large Dutch population study called the European Prospective Investigation into Cancer and Nutrition (EPIC-NL)47 followed 37,514 participants over thirteen years with food frequency questionnaires (see Figure 9.7). Those who drank moderate amounts of coffee had modest protection against heart disease. However, drinking more than six cups of coffee per day seemed to attenuate some of those benefits. This data is more or less in line with results from other studies that indicate moderate coffee drinking (three to four cups) might have some potential benefits.
Fig. 9.7: Cardiac protection with tea and coffee (EPIC-NL)
In one of the most comprehensive reviews on the subject, Poole and colleagues concluded that consuming three to four cups of coffee per day was associated with the largest benefit for reducing all-cause mortality, cardiovascular mortality, and cardiovascular disease.48 This also included an 18 percent lower risk of cancer, with no evidence of harmful associations. European studies also found that heavy coffee drinkers had a 22 percent lower risk of all-cause mortality.49 An analysis of three large prospective cohorts found that drinking one to five cups of coffee per day was associated with a significantly lower risk of mortality with evidence of a dose-response relationship.50
ADD HONEY TO YOUR COFFEE
To add a little natural sweetness to your coffee, you can add some raw honey. Rainforest1st Wild Tualang Honey appears to be the only available FDA-certified raw tualang honey (www.rainforest1st.com). Tualang honey is a very dark honey, which generally contains more antioxidants and nutrients compared to lighter honeys. The darker the honey, the better it is for your health.
MECHANISMS OF BENEFITS
Coffee is a rich source of chlorogenic acid, which is metabolized to caffeic acid and then ferulic acid in the body. Blood levels of ferulic acid are even higher than caffeic acid in the hours following coffee consumption,51 and this may drive many of the health benefits. In rodents, ferulic acid is protective against Parkinson’s disease52 and also increases the synthesis of the antioxidant glutathione.53 Ferulic acid can act as a scavenger, stabilizer, and chain-breaker of free radicals due to its phenolic nucleus and its highly conjugated structure, which may help to protect against UV radiation and lipid peroxidation.54 Ferulic acid also has been noted to protect against cerebral ischemia-reperfusion injury,55 and it reduces the harm from the inflammatory cytokine TNF-alpha.56
POTENTIAL SIDE EFFECTS OF COFFEE
Potential adverse effects of caffeinated coffee may include insomnia, increased urination and thirst, dehydration, palpitations, and tremors. In the elderly, bone loss is a potential adverse effect.57 Caffeine is a diuretic and can cause an increased loss of sodium, chloride, and calcium from the urine.58 Each cup of coffee causes an additional 437 milligrams of urinary sodium loss, so drinking four cups of coffee would require eating an extra half teaspoon of salt to replace those losses.59
Consuming coffee and caffeine during pregnancy can increase the risk of preterm labor and low birth weight. Also, drinking coffee on a regular basis can lead to physical and psychological dependence. However, dependence might be an advantageous side effect because it helps to reinforce daily consumption of coffee, which is associated with a broad range of health benefits.
We think of salt more like a poison than an essential mineral. The Dietary Guidelines, health agencies, and doctors tell us that the lower the salt intake, the better. But does any real evidence support this notion? Where does the idea that salt is bad for us come from? In this chapter, we review the key players in the history of the low-salt dogma and show how eating more salt can actually improve your health.
Like salt, magnesium is an important mineral. However, unlike the heavy clouds hovering over the white crystal, magnesium has a health halo—and for good reason. Magnesium is vital for more than 600 reactions in the body, and many of us are being depleted of magnesium due to lifestyle choices, chronic diseases, and medications. Salt and magnesium are intricately connected, which is a relationship long forgotten. In the following pages, we explain the benefits of magnesium, what factors cause its deficiency, and which forms of magnesium are the best for supplementation.
Low-Salt Advice: Clear, Simple, and Wrong
There seems to be one piece of advice upon which virtually all nutritional authorities agree. Eating less salt will lower your blood pressure and therefore reduce the risk of heart disease. And people are listening: More than 50 percent of Americans try cutting back on salt with about 25 percent being advised by their health-care professional to do so. Americans eat approximately 1½ teaspoons of salt per day, but the recommended amount is less than half this quantity. This advice is clear, simple, and just plain wrong.
We have not always condemned salt as a dietary villain. As Dr. DiNicolantonio covers in his book, The Salt Fix, entire cities have risen and fallen from the salt trade. People fought wars over salt. Throughout most of human history, salt was a vital nutrient. The word salary derives from the Latin word for salt—sal. Biblical passages speak of “salt of the earth.” A common English saying is that somebody is “worth their salt.” This linguistic evidence points to salt being a prized and important commodity rather than something that should be limited and shunned. When did we start to fear our natural craving for salt?1
In the 1950s, Lewis K. Dahl, a researcher from Upton, New York, noticed that people who ate less salt had less hypertension (high blood pressure), a key risk factor for heart disease.2 Based on the limited data he had collected, Dahl promoted the notion that too much salt was the primary cause of hypertension and cardiovascular disease.
Dahl began to look for supporting evidence using genetically engineered salt-sensitive rats in his lab. Feeding massive amounts of salt to these rats predictably caused high blood pressure. Drawing conclusions from this study is fairly ridiculous. Because these rats were genetically manipulated to develop high blood pressure with salt, the results of this study were not proof of anything. The equivalent amount a human would need to consume is 4½ cups of salt per day, which is an outrageous amount! But Dahl extrapolated inappropriately to normal human babies and suggested that a high salt intake might contribute to early childhood mortality.3 He was so influential with his assertion that food manufacturers began reducing salt in baby formula.
Dahl conjectured that salt was mildly addictive, and our cravings were triggered by eating it.4 In 1976, Meneely and Battarbee suggested that Americans consume the bare minimum of salt compatible with life—just 3 grams of salt per day.¹ This unproven idea carried over into the first Dietary Goals for the United States in 1977, thereby becoming enshrined in nutritional lore. However, this recommendation was based almost solely on the questionable data from the studies of the genetically altered rats, and no human evidence existed at that time.
But the horse was already out of the barn. The government, the guidelines, and the media had already convinced the American public that salt was bad for their health despite the lack of any scientific backing. Over and over “experts” repeated the refrain of “avoid too much sodium.” Repetition achieved what common sense could not, and salt restriction was written into dietary gospel. The first systematic review of clinical trials testing low-salt diets on blood pressure would not be published for almost fifteen years after the low-salt dogma had been almost universally accepted. Evidence would later suggest that our health woes were caused by another white crystal: sugar.5
By 1982, salt had been called “A New Villain” on the cover of Time magazine. The 1988 publication of the INTERSALT study seemed to seal the deal. This massive study laboriously measured salt intake and blood pressure in fifty-two centers across thirty-two countries. Sure enough, the higher the salt consumption, the higher the blood pressure. The idea that reducing dietary salt helped lower blood pressure seemed like a slam dunk, although the effect was quite small. A 59 percent reduction in sodium intake lowered the blood pressure by only 2 mmHg. For example, if your starting systolic blood pressure was 140 mmHg, then severe salt restriction co
uld lower that to 138 mmHg. That’s nothing to boast about. Further, no data existed as to whether this lower blood pressure would translate into fewer heart attacks and strokes. But based on this influential study, in 1994 the mandatory Nutrition Facts Label proclaimed that Americans should eat only 2,400 milligrams per day (about one teaspoon of salt).6 Yet the stubborn fact remained that virtually every healthy population in the world eats salt at levels far greater than that recommendation. The dramatic improvements in health and life span of the last 50 years have occurred during a period where almost everybody was considered to be eating too much salt.
We largely base our belief in the benefits of low-salt consumption on misinformation and myth-information. We assume that too much salt is a recent phenomenon brought on by the increased consumption of processed foods. Dahl, for example, claimed in his writings that widespread use of salt as a condiment was uncommon until modern times, but we need only to study a little bit of history to see that this assertion was false.
Data from military archives from the War of 1812 show that soldiers (and presumably the rest of Western society) ate between 16 and 20 grams of salt per day.7 Soldiers were given a daily salt ration of 18 grams per day despite its high cost to the army. American prisoners of war complained bitterly that their 9 grams per day of salt was “scanty and meager.” It was only after World War II, when refrigeration replaced salting as the primary means of preserving food, that Americans lowered their average salt intake to 9 grams per day, where it has remained since. During the century before WWII, there was no concern of excess deaths from heart disease, stroke, or kidney disease—the main threats used to scare us into lowering our salt intake.
THE TIDES TURN
From the very beginning, it should have been obvious that lowering salt could not save lives. There were innumerable high-salt-eating cultures that had no adverse health consequences. The Samburu warriors8 consume close to 2 teaspoons of salt per day, even going as far as eating salt directly from the salt licks meant for their cattle. Despite eating all this salt, their average blood pressure is just 106/72 mmHg and does not rise with age. In comparison, about one-third of the adult population in America is hypertensive, with a blood pressure of at least 140/90 mmHg or higher, despite the effort of trying to comply with dietary guidelines to reduce salt. For reference, normal blood pressure is less than 120/80 mmHg and generally rises with age in the United States. Villagers from Kotyang, Nepal eat 2 teaspoons of salt per day, and the Kuna Indians eat 1½ teaspoons of salt per day, with no hypertension.9 The chart in Figure 10.110 shows many other examples that contradict Dahl’s hypothesis that a high-salt diet causes hypertension.
Fig. 10.1
The most recent survey of global salt intake from 2013 shows that no area of the world conformed to either the American Heart Association (AHA) or the World Health Organization (WHO) recommendations for salt restriction. The central Asian region had the highest salt intake, followed closely by the Asia Pacific region including Japan and Singapore. The Japanese diet is notoriously high in sodium because of the soy sauce, miso, and pickled vegetables they eat. The Japanese seem to suffer no ill effect and have the world’s longest life expectancy at 83.7 years. Singapore is third in life expectancy at 83.1 years. If eating salt was so bad for health, how could the world’s longest-lived people also eat one of the world’s saltiest diets?
Scientific concerns about the validity of the low salt advice started in 1973 when an analysis11 found six populations where the average blood pressure was low despite an extremely high-salt diet. For example, those living in Okayama, Japan, consumed more salt than most nations today (up to 31/3 teaspoons per day), and yet had some of the lowest average blood pressures in the world.
In some cases, blood pressure decreased as salt intake increased. For example, North Indians consumed an average salt intake of 2½ teaspoons (14 grams) per day but maintained a normal blood pressure of 133/81 mmHg. In South India, average salt intake was about half that of North India, but the average blood pressure was significantly higher at 141/88 mmHg.12 If salt was truly one of the major determinants of blood pressure, then this anomaly should not exist.
Fig. 10.2: INTERSALT: higher salt intake, lower blood pressure13
But there was still the question of the massive INTERSALT study, which people often cite as the ultimate proof of the harm of eating too much salt (see Figure 10.2). Further analysis of the data began to paint a significantly different picture. Researchers included four primitive populations (the Yanomamo, Xingu, Papua New Guinean, and Kenyan) in the initial analysis, and those societies had significantly lower sodium intakes than the rest of the world. (One had a sodium intake 99 percent lower!) However, they also lived a vastly different, primitive lifestyle from the others. These outliers had limited generalizability to the rest of the world, and, because they were such outliers, they had an outsized effect on the averages.
These four primitive societies differed from modern ones in far more than just diet. For example, the Yanomami Indians of Brazil still live traditionally, hunting and gathering just as they had done centuries ago. They practice endocannibalism (in which people consume the ashes of loved ones) because they believe it keeps them alive. They don’t eat processed foods (because they don’t have any). They don’t use pesticides or preservatives. They don’t use modern medicine. Comparing a Yanomami Indian living in the jungles of the Amazon to a person living in the jungles of New York is hardly fair. Isolating a single component of their diet (sodium) and proclaiming it to be solely responsible for high blood pressure is the pinnacle of bad research. You could just as easily conclude that wearing loincloths and eating the ashes of your dead relatives lowers your blood pressure.
There were other concerns with the INTERSALT study, too. Two populations (Yanomami and Xingu Indians), when studied further, had the near absence of a specific gene D/D of the angiotensin-converting enzyme (ACE), which put these populations at extremely low risk of heart disease and hypertension regardless of how much salt they ate. Thus, low sodium intake may not be the major or even minor contributor to low blood pressure in these groups. Rather, these two populations may have low blood pressure for genetic rather than dietary reasons.
In cases where there are significant outliers, the proper scientific analysis would be to analyze the information by removing these outliers to see if the original salt hypothesis still holds. When those four primitive populations were removed, and the remaining forty-eight Westernized populations were analyzed, the results were opposite the original findings. Blood pressure decreased as salt intake increased. Eating less salt was not a healthy practice; it was harmful. We shouldn’t be eating less salt. We should be eating more. This study would not be the only one to confirm these surprising results.
Fig. 10.3: NHANES I: Higher salt intake, lower risk of death14
We have consistent evidence from American studies that shows that eating less salt is associated with poor health. The National Health and Nutrition Examination Survey (NHANES) is a periodic, large-scale survey of American dietary habits. The first survey15 found that those people who ate the least salt died at a rate 18 percent higher than those who ate the most salt (see Figure 10.3). This finding was a highly significant and exceedingly disturbing result. Eating low-salt diets was not healthful but harmful. It also confirmed the problem of salt restriction seen in the INTERSALT study.
The second NHANES survey confirmed the horrible news that a low-salt diet was associated with a staggering 15.4 percent increased risk of death. Other trials found an increased risk of heart attacks of eating a low-salt diet in treated hypertensive patients. Those were precisely the patients to whom doctors had been recommending a low-salt diet! We weren’t healers; we were killers.
In 2003, the Centers for Disease Control, part of the U.S. Department of Health and Human Services, became worried and asked the Institute of Medicine (IOM) to take a fresh look at the available evidence to focus on mortality and heart disease rather than the
surrogate outcome of blood pressure.16 In other words, the IOM took on the task of finding out if salt restriction could reduce heart attacks and death, which are outcomes that matter more than merely making a few blood pressure numbers temporarily look better.
After an exhaustive search of the medical literature, the IOM made several major conclusions. Although low-salt diets could lower blood pressure, “Existing evidence… does not support either a positive or negative effect of lowering sodium intake to less than 2,300 milligrams per day in terms of cardiovascular risk or mortality in the general population.”17 That is, eating less salt did not reduce the risk of heart attack or death. However, in patients with heart failure, “The committee concluded that there is sufficient evidence to suggest a negative effect of low sodium intakes.” Oh my. In other words, in patients with heart failure, eating less salt was bad, very bad. One of the very first things that millions of doctors learned in medical school was to advise patients with heart failure to eat less salt. This was exactly wrong, and decidedly deadly, advice.
But dogma is hard to change. Sticking our heads in the sand is easier than admitting we were wrong. Ignoring the advice of the IOM, the 2015 Dietary Guidelines continued to recommend reducing sodium intake to less than 2,300 milligrams of sodium (about one teaspoon of salt) per day, whereas the American Heart Association recommends less than 1,500 milligrams of sodium per day.
