Drinking coffee is associated with a lower overall risk of death, at least if you're a middle-aged Mediterranean, says a Spanish study that looked at the topic, exclusively in middle-aged Mediterraneans. Meanwhile, a Finnish study found that higher salt consumption doubles the risk of heart failure. In Finland.
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Both were relatively big studies, which automatically renders the results more interesting. It bears noting however, about the salt, that "required amounts" differ enormously depending on our physiology, metabolism, geographical location, state of slothfulness, sweating, and a lot more. A middle-aged Mediterranean hoeing the wheat fields in the midday sun is going to need more salt with lunch than a Nordic couch potato sleeping through the long winter night. (Scientific American summed up the origins of concern about salt, and home truths, in 2011.)
This latest coffee research followed other reports on coffee's benefits in net terms: Time for one noted that some antiquated studies had failed to notice that some adverse effects reported by study participants were from smoking, not caffeine. After factoring in confounding factors, coffee drinkers do not seem more prone to heart trouble or cancer than non-imbibers, studies have indicated.
The latest Spanish study reports on monitoring of 20,000 Mediterraneans, aged nearly 38 on average upon enrolment, whose health was followed up for ten years. During that time, 337 of the test subjects died (from various causes, not coffee), note the Spanish researchers, from Universidad de Navarra.
Among those that did not die, drinkers of at least four cups of coffee a day had a 64% lower risk of all-cause mortality than those who never or almost never consumed coffee, says the paper. It doesn't postulate why. Maybe they were simply awake enough to see trouble coming.
Anyway, the coffee boost was most pronounced in people aged 45 and up. For them, drinking two additional cups of coffee a day was associated with a 30% lower risk of mortality during the 10-year follow-up, the scientists report. Below that age, those two cups had little observed effect on mortality rates.
Conclusion from Dr Adela Navarro, a cardiologist at Hospital de Navarra, Pamplona, Spain and the lead author: "Our findings suggest that drinking four cups of coffee each day can be part of a healthy diet in healthy people."
Salt however may be less beneficial when it comes to the Finland, where a 12-year study in more than 4,000 subjects found a doubled risk of heart failure.
"The heart does not like salt. High salt intake markedly increases the risk of heart failure," stated Prof Pekka Jousilahti, research professor at the National Institute for Health and Welfare, Helsinki. Crucially adding: "This salt-related increase in heart failure risk was independent of blood pressure."
Taken with a grain of salt
The numbers: People who ate more than 13.7 grams of salt daily doubled their risk of heart failure compared to people eating less than 6.8 grams, the study concluded, noting that the World Health Organization recommends a maximum of 5 grams per day.
Six grams is a teaspoon of salt, so five grams is a little less than that. But even that figure is a very vague guideline.
We need to eat salt. Table salt is sodium chloride and we need the sodium for nervous-system transmissions, for cellular functioning and to prevent dehydration. The word "salary" even originated in the Latin word for salt. If we become depleted and don't eat salt, we will die.
The question is how much salt we need. The "physiological need" for salt depends on a host of parameters, from our body weight to the weather. Prof. Jousilahti estimates the physiological need at between 2 and 3 grams a day. Others figure the requirement at around 5 grams a day. In fact, that could be far short of what you need, depending on what you do and what you eat.
Deploring the absence of even similar standards and guidelines, let alone uniform ones, the U.S. National Institutes of Health dryly noted, "Fluid and electrolyte losses resulting from prolonged sweating must be replaced to prevent imbalance in body fluids, however guidelines for this replacement are often conflicting." (In English, if you sweat like a horse and only drink water, without replenishing your mineral losses, you could dilute your plasma and become hyponatremic.)
So the NIH inquired how much men working hard sweat in the summer and winter, and what should be done about it.
People can lose over 1.5 liters of sweat an hour in great heat, which seems to be more likely than less, given climate change. The NIH study concluded that people working in even moderately hot conditions for ten hours on average may lose between 4.8 and 6 grams of sodium, which is equivalent to 12 to 15 grams of salt – or more.
Eating half teaspoon of salt a day isn't going to cut it for people like that. At least, if they have a cup of coffee while doing the math, that can only be helpful.