Protein 101
Protein is a macronutrient that is essential for the growth, repair, and maintenance of the body's tissues and organs. It is made up of smaller units called amino acids, which are linked together in various sequences to form different types of proteins. There are 20 different amino acids, and the specific arrangement of these amino acids determines the structure and function of each protein. Of these amino acids, 9 are considered essential—meaning your body cannot synthesize them—so you must get them from food.
Protein is obtained through the diet from various sources, including animal products like meat, fish, eggs, and dairy, as well as plant-based sources such as beans, lentils, nuts, and seeds. It is an essential part of a balanced diet and is required for overall health and wellbeing.
How Much Protein Do You Need?
Protein needs depends on various factors such as your age, sex, weight, physical activity level, and overall health goals. According to the U.S. government, the recommended daily allowance (RDA) for protein intake is 0.8 grams of protein for each kilogram of body weight, or 0.36 grams per pound of body weight. For a 140 pound woman, for example, this translates to 50 grams of protein or the amount in a 6-ounce portion of chicken breast.
However, this is a basic guideline and may not be sufficient for everyone. Most experts agree that the RDA’s protein recommendation is woefully inadequate for optimal health. The RDA reflects the basic need of a sedentary individual to prevent illness. Individuals who are more physically active, athletes, pregnant or lactating women, and older adults may require higher protein intake. For example, athletes and those engaged in intense physical activity might need 1.2 to 2.2 grams of protein per kilogram (0.55-1 grams per pound) of body weight per day to support muscle repair and growth.
For older adults (generally defined as over 60 years old), increasing protein intake to 1.2 to 1.6 grams per kilogram (0.55-0.73 grams per pound) of body weight may be beneficial, as protein plays a crucial role in preserving muscle mass and overall health during aging.
Benefits of Eating Adequate Protein
Weight management during perimenopause: Prioritizing protein during perimenopause and menopause may ward off weight gain. The research suggests that the body's appetite for protein increases during perimenopause (due to hormonally-induced tissue protein breakdown) but if protein requirements are not met, women over-consume other forms of energy. A diet rich in protein, coupled with regular exercise, especially strength training, can help regenerate muscle mass. More muscle mass contributes to a faster metabolism, aiding in weight management during menopause.
Age better with more protein: Getting enough protein is emerging as a key factor in successful aging. As people age, protein becomes even more crucial as it helps maintain muscle mass, supports immune function, and aids in overall tissue repair and maintenance. Studies by experts indicate that after age 40, muscle mass may decrease by up to 8% every decade, potentially resulting in a 16% loss of muscle mass for postmenopausal women by age 60. Beyond age 60, the rate of muscle mass loss further accelerates to around 10 to 15% per decade. This decline in muscle mass often leads to sarcopenia, a condition characterized by weak muscles, frailty, and reduced mobility. Numerous clinical studies have demonstrated that consuming adequate protein can help counteract unwanted muscle loss and weakness, promoting better overall health and physical function. Research suggests that for older adults, protein intake of around 1.2 to 1.6 grams per kilogram (0.54 to 0.73 grams per pound) of body weight per day supports healthy aging and preserve muscle mass. For example, if an older adult weighs 70 kilograms (154 pounds), their protein intake may range from approximately 84 to 112 grams per day.
Reduce your risk of dementia: According to recent studies, adults over age 65 may have healthier brains if protein intake is at least double the RDA, or 1.6 grams per kilogram of body weight, or 0.73 grams per pound.
The precise way in which protein supports the aging brain remains uncertain. It could involve a direct mechanism, such as supplying specific amino acids essential for enhancing neurotransmitters. Alternatively, protein intake might indirectly benefit the brain by averting muscle loss and frailty, which could otherwise result in a less dynamic and engaged brain-healthy lifestyle. Regardless of the exact mechanism, individuals who retain muscle mass as they age generally exhibit more robust brain health.
The Cache County Dementia Progression Study showed a strong association between low protein intake and dementia. In fact, the lower the intake, the more severe the dementia.
In this older study of adults over 65, higher protein intake was positively associated with memory function. Those adults with the highest protein intake also had the lowest incidence of mild cognitive impairment.
In this study published in the Journal of Alzheimer’s Disease, healthy older adults with a high protein (and fiber) intake had less amyloid-β accumulation in the brain, when compared to those with medium to low intake. In fact, those in the lowest tier of protein intake were 12 times more likely to have a high burden of amyloid protein visualized on brain imaging studies.
Is It Harmful to Eat Too Much Protein?
The belief that excessive protein consumption leads to kidney problems or other health issues is a misconception. Long-term consumption of protein at 2 grams per kilogram body weight per day (or 0.9 grams per pound per day) is safe for healthy adults. Nevertheless, individuals with specific kidney conditions should consult their doctors about the most appropriate protein intake. Protein that isn't utilized for muscle development or other bodily functions is efficiently eliminated through the kidneys as urea.
In summary, it's wiser to lean towards consuming more protein than insufficient amounts. Achieving an optimal protein intake is essential for both your body and cognitive health as you grow older.