Jane Harris

Do potato eaters live longer or shorter lives than non-potato eaters? Is there a link between potato intake and the incidence of hypertension? Harvard researchers followed the diets and diseases of more than 100,000 men and women for decades and found that those who ate potatoes on most days—not only French fries and potato chips, but even mashed, boiled, or baked—appeared to be at higher risk of developing high blood pressure. But what do people put on potatoes? Salt, not to mention butter, so might the potatoes just be innocent bystanders? The researchers made attempts to tease out the effects of salt and saturated fat, and there still seemed to be a link between potato consumption and high blood pressure. Maybe potato eaters are meat-and-potatoes people. After all, these same Harvard researchers found that meat, including poultry, seemed to be associated on its own with an increased risk of hypertension, and the same goes for even a moderate amount of canned tuna. So, in the po...

Does the link between white potatoes and diabetes extend to non-fried potatoes without butter or sour cream? The trouble for white potatoes began in 2006, when the Harvard Nurses’ Health Study, which had followed the diets and diseases of tens of thousands of women for 20 years, found that greater potato intake was associated with a greater likelihood of getting type 2 diabetes. However, of the hundred or so pounds of potatoes Americans eat every year, most are in the deep-fried forms of potato chips, french fries, or other processed products. What happened when they looked specifically at mashed or baked potatoes? They found the same link with diabetes. Okay, but what might potato eaters eat more of? Maybe I should rephrase that: What might meat-and-potatoes people eat more of? Indeed, people who ate more potatoes ate more meat, and we know that animal protein may be associated with increased diabetes risk. But the researchers tried to statistically adjust for that and still fou...

Prunes, figs, and exercise are put to the test as natural home remedies for constipation. The act of defecation is very private and the object of cultural taboos, so much so that it’s rarely thought of, even by physicians—but it should be. Constipation accounts for three million annual visits to doctors in the United States and 800,000 emergency room visits. Depending on how you define it, up to 80% of the population may be suffering. Even people who don’t think they’re constipated may very well be clinically constipated. A quarter of so-called healthy study participants reported experiencing “incomplete emptying,” and about half “indicated increased straining.” In fact, more than half had found blood on their toilet paper within the past year. In severe cases, the blood pressure spike associated with straining while passing stool can even trigger a heart attack or a stroke. There are drugs for it. There are always drugs, resulting in side effects like nausea, diarrhea, headach...

Glycidol may help explain why people who eat fried foods get more cancer. “The main purpose of frying is to produce foods with good consumer acceptability. However, not all acceptable foods are safe.” Food chemists have been very interested in the newly discovered toxic compounds produced by frying. We’ve been refining vegetable oils for more than a century, but only recently have we discovered that this can produce concerning compounds such as 3-MCPD and, even worse, glycidol. 3-MCPD is considered a nongenotoxic carcinogen with a tolerable daily intake, while glycidol is a known genotoxic carcinogen, meaning it can cause cancer by directly damaging our DNA, as I discuss in my video The Carcinogen Glycidol in Cooking Oils . If a compound is not directly DNA-damaging, it’s assumed that it acts through a mechanism that exhibits a threshold; a so-called no-effect level may exist, a level below which it may not be harmful. But if a compound does damage DNA, it’s generally assumed to...

What does an anti-inflammatory diet look like? “Intervention studies to enhance healthy ageing need appropriate outcome measures, such as blood-borne biomarkers, which are easily obtainable, cost-effective, and widely accepted.” We need blood-borne biomarkers of mortality risk. For example, having higher levels of C-reactive protein in your blood may increase your risk of dying prematurely by 42%. C-reactive protein is one of the most widely used inflammatory biomarkers for predicting mortality, but those with the highest levels of interleukin-6 (IL-6), another marker of inflammation, may increase premature death risk by 49%. What can we do to bring it down? I’ve previously talked about foods that can contribute to inflammation, like meat and sugar, versus foods like nuts that don’t. But what about anti-inflammatory foods that actually attenuate that inflammation? What happens when blueberries are added to a high-fat, high-glycemic-load meal consisting of white potatoes, white br...

Inflammatory markers can double within six hours of eating a pro-inflammatory meal. Which foods are the worst? Excessive inflammation may play a role in a number of leading causes of death and disability, including type 2 diabetes, obesity, and heart disease. “But what are the stimuli that jumpstart the destructive inflammatory cascade?” You typically hear about the pro-inflammatory nature of a chronic high-fat diet, but the inflammatory effect “may not be limited to chronic intake but may be evident after the consumption of a single meal.” Within hours after eating an unhealthy meal, inflammatory markers like interleukin-6 (IL-6) can skyrocket, doubling within six hours. The majority of studies show an increase in IL-6 after consuming a high-fat meal. But the meals they tested weren’t just filled with meat, eggs, dairy, and oil, but also junky refined carbohydrates like white flour and added sugar. When people are given essentially straight butter fat and no carbs, they can still ...