In health and nutrition news for the lay public fats and carbohydrates garner the lion’s share of attention. The second half of the 20th Century saw a nearly across-the-board demonization of all fats and then a shifting of the focus specifically to saturated fats. In the new millennium the pendulum has begun to swing toward carbohydrates with a menacing finger now pointing toward highly refined and processed sugars and grains as being causative agents in type 2 diabetes obesity and cardiovascular disease. The macronutrient that seems to fly under the radar is protein. This is a shame because adequate protein is critical for good health and the general public is largely unaware of and greatly underappreciates the numerous beneficial roles of protein. Consuming adequate protein is especially important for older people many of whom are likely to be dramatically under-consuming it.
Red meat has long been the whipping boy of mainstream nutrition and dietetics despite it being loaded with micronutrients some of which are difficult or downright impossible to obtain from plant foods. The long-term demonization of red meat and perhaps even the generally accepted—if erroneous—bias toward “plant-based” diets as being the most healthful have perhaps led some people to dramatically decrease their intake of animal proteins. There is also a great deal of misinformation regarding the effects of protein intake on bone health and kidney function. It is not accurate that an increase in dietary acid load from increased protein leads to a reduction in bone mineral density via alkalinizing calcium being leached from the bones in order to maintain a healthy blood pH. It’s true that increasing protein intake tends to result in increased urinary calcium excretion but this is coupled with an increased calcium absorption as well with no adverse effects measured in bone health. In fact diets low in protein are associated with reduced bone density and increased rates of bone loss. (Let’s keep in mind that aside from the calcium hydroxyapatite mineral matrix bones are largely made up of protein.) In a trial that compared the effects of low medium and high protein diets on markers of bone health “the highest protein diet resulted in hypercalciuria with no change in serum parathyroid hormone” while the low protein diet induced secondary hyperparathyroidism within just four days. Researchers attributed this outcome of the low protein diet to a reduction in intestinal calcium absorption.
As for kidney health individuals with pre-existing kidney damage might have to be careful but in otherwise healthy individuals higher protein intakes have not been shown to induce renal dysfunction. Higher protein diets—whether the protein is animal or plant-sourced—are associated with benefits for cardiometabolic health reduced adiposity and show no apparent adverse effects on kidney function. Moreover considering that the Food and Nutrition Board of the Institute of Medicine of the U.S. National Academies of Sciences has written that the acceptable range of protein intake as a percentage of total calories for adults is 10-35% and the vast majority of older people are not consuming anywhere near a 35% protein diet it is unlikely that anyone runs the risk of consuming “too much” protein. If anything government recommendations for protein intake are inadequate to meet the needs of older people.
With sarcopenia and dynapenia playing a significant role in declining health mobility and independence in one’s golden years building and maintaining muscle mass is a crucial aspect of healthy aging. The current U.S. guidelines for protein intake for adults—0.8 grams of protein per kilogram of body weight per day—were shown to have adverse effects on nitrogen balance in healthy ambulatory subjects ages 55-77 so imagine the effects in those who are already frail and infirm or who are not even meeting that relatively low recommendation for protein intake. One study suggests that a daily protein intake of 1.0-1.25 grams per kilogram of body weight—one and a half times as much—is a more reasonable target for the elderly and another suggests 1.0-1.3 grams per kilogram in order to maintain nitrogen balance. This is likely far more protein than the average older person is eating particularly if they live alone.
Older individuals who live by themselves are more likely to pour themselves a bowl of cereal for dinner or boil some noodles rather than go to the bother of grilling a steak or baking a pork chop. Moreover many older people have trouble chewing tough cuts of meat which makes soft foods—rice mashed potatoes oatmeal (all high in carbohydrate)—even more appealing. And of course digestive fire tends to decline with age so there are multiple obstacles to older people increasing quality protein intake. But these are not insurmountable obstacles. For example tough cuts of meat can be made fork-tender in a slow cooker and these include cuts that are rich in collagen and connective tissue—such as oxtails and beef or lamb shanks—which may be particularly beneficial for people with joint pain and degeneration. People who have difficulty chewing can enjoy ground beef lamb pork or turkey loose sausage meat loaf and other protein preparations that are easier on the teeth. There’s also cottage cheese and yogurt for those who do well with dairy and for those who can tolerate the higher carbohydrates beans are a good choice for a high-protein food that’s easy to chew.
Bottom line: older individuals who are likely to be skimping on protein may be the people who need protein the most. Higher protein intakes are associated with reduced frailty in older people and some researchers suggest that the minimum daily protein intake for adults age 65 and over should be raised to 1 gram per kilogram of body weight.
The controversies surrounding dietary fats and carbohydrates are not without meaning but we seem to ignore the critical role of protein to our detriment.