How to Assess Protein Requirements in Older Adults

As we age, protein requirements become increasingly important to maintain health and function. However, a recent analysis of data from the National Health and Nutrition Examination Survey (NHANES) found that many Americans over age 50 do not meet recommended daily protein intake.¹ This deficiency puts you at risk for a variety of health problems, especially as you age.

This study examined protein intake, associated dietary patterns, and physical function in adults aged 51 years and older, highlighting the importance of adequate protein intake for healthy aging.

However, it is important to optimize your protein intake. This is because consuming too much or too little can cause problems. Eating too much protein can harm your kidney health and homocysteine ​​levels. But eating too little puts you at risk for sarcopenia, an age-related condition characterized by loss of muscle mass and function and weakness.²

The important role of protein in the body

You may not think about it often, but protein is working tirelessly in our bodies every minute of the day. These amazing molecules are essential for building and repairing tissues, including muscles and organs. It is also important for the proper functioning of enzymes, hormones, and immune system components. But what exactly are proteins made of?

Amino acids are made up of smaller units called amino acids, some of which the body cannot produce on its own. These “essential” amino acids must come from your diet, so it is important to eat protein-rich foods such as meat, eggs, and dairy products. By ensuring your diet is diverse with these protein sources, you provide your body with the building blocks it needs to function optimally.

When you eat protein, your body doesn’t simply absorb the entire protein. Instead, it breaks down proteins into individual amino acids. As Elsevier’s education platform Osmosis explains,³ These amino acids are reformed into new proteins in the body.

These newly formed proteins perform a wide range of functions, from fighting infections to helping cells divide. At its most basic, proteins are like a series of beads, each representing an amino acid. These strings are then twisted and folded into complex shapes, giving each protein its unique structure and function.

Most amino acids have a central carbon atom bonded to an amino group, a carboxylic acid group, a hydrogen atom, and a unique side chain. Because of this structure, they are called amino acids.

20 Amino Acids Your Body Needs

Nature produces hundreds of amino acids, but the body uses only about 20 of them to make almost all the types of proteins it needs. Those 20 proteins are:

Each of these amino acids plays an important role in body functions. For example, leucine is important for muscle growth and recovery. However, not all amino acids in the diet are created equal. Of the 20 amino acids the body uses, some are considered non-essential because the body produces them on its own. These include alanine, asparagine, aspartic acid, glutamic acid, and serine.

But don’t be fooled by the term “non-essential.” These amino acids are still important for your health. It is said to be non-essential simply because you do not need to consume it directly from your diet. On the other hand, there are nine essential amino acids that the body cannot produce: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

You get this from the foods you eat, so a varied, protein-rich diet is very important.

The third category of amino acids that fall between essential and non-essential amino acids are conditionally essential amino acids. These include arginine, cysteine, glutamine, glycine, proline, and tyrosine. Under normal circumstances, the body produces these amino acids. However, during illness, stress, or strenuous physical activity, the body’s ability to produce these amino acids may not be sufficient to meet the increased demand.

In these situations, it is necessary to obtain these amino acids through the diet. That’s why your protein needs vary depending on your age, health, and activity level.

The surprising truth about protein intake in older adults

You might assume that most Americans easily meet or exceed their protein requirements, but the data tells a different story. A significant proportion of older adults (31% to 50%) do not meet the very conservative recommended protein intake of 0.8 grams per kilogram of body weight per day.⁴

As we get older, the problem becomes more pronounced. This is because older people are less likely to meet protein recommendations. This trend is particularly concerning because it coincides with the age group in which sarcopenia is more prevalent. It’s not just your muscles that suffer when you don’t meet your protein needs.

Studies have shown that adults who do not meet protein recommendations are more likely to have low intakes of several essential nutrients.⁵ It contains fiber, various B vitamins, choline, vitamins C, A, D, E and K, as well as important minerals such as zinc, calcium, phosphorus, magnesium and selenium. Many of these are considered nutrients of public health concern due to widespread underconsumption. Deficiencies in these nutrients have far-reaching health implications.

For example, zinc deficiency impairs immune function and slows wound healing, which becomes increasingly problematic as we age. The combination of low protein and micronutrient deficiencies can increase the risk of common age-related problems such as falls, bedsores, osteoporosis, muscle weakness, and even premature death.

The connection between proteins and body functions

Your ability to perform daily activities is also closely related to protein intake. The study found a positive association between achieving recommended protein intake and self-reported physical function.

If you do not meet your protein requirements, you are more likely to experience limitations in activities of daily living, including bending, squatting, kneeling, standing or sitting for long periods of time, walking upstairs, preparing a meal, or walking a quarter mile.⁶

These findings are consistent with other studies showing that high-protein diets improve physical function, especially in activities such as walking, climbing stairs, and lifting heavy objects.⁷ Although the current study does not prove causality, it suggests that ensuring adequate protein intake may play an important role in maintaining independence and quality of life as one ages.

Benefits of Increasing Protein Consumption for Seniors

Epidemiological and experimental evidence supports the notion that, in some cases, older adults may benefit from protein intake higher than the currently recommended dietary allowance (RDA).

A seminal study from the Health, Aging, and Body Composition Study found that older community residents who consumed approximately 1.2 grams of protein per kilogram of body weight each day gained 40% more lean muscle tissue in their arms and legs over a three-year period. It was found that there was a % decrease. compared to people consuming 0.8 grams per kilogram.⁸

Similar results were observed in two independent cohorts, the Women’s Health Initiative and the Framingham Offspring study, where protein intake of approximately 1.2 grams per kilogram of body weight was associated with better grip strength preservation.⁹ Several systematic reviews and meta-analyses have shown that protein intake above the RDA is associated with improved physical function and reduced risk of sarcopenia in older adults.¹⁰

These findings have led several expert groups to issue updated nutritional recommendations for maintaining and improving lean body mass and function in older age, suggesting a daily protein intake of at least 1 to 1.2 grams per kilogram of body weight for healthy older adults.¹¹

Find the protein sweet spot

So how do you determine the right amount of protein for your body? Research shows that too little or too much protein can be detrimental to muscle health. Low protein intake (less than 0.8 grams per kilogram of body weight per day) was associated with a lower risk of muscle mass loss but did not provide significant protection against sarcopenia overall. In this study, the optimal range was 0.8 to 1.3 grams of protein per kilogram of body weight per day.

In general, protein should make up about 15% of your daily calories. About one-third, or about 5%, of this protein should be collagen. More specifically, most adults need about 0.8 grams of protein per pound of their ideal weight (ideally, but not necessarily your current weight), while Europeans need about 1.76 grams of protein per kilogram.

So while the existing recommendation is 0.8 grams per kilogram of total body weight, my recommendation is 0.8 grams per kilogram of ideal body weight, including for older people. This ends up being much higher than existing recommendations.

To determine your ideal weight, you need to know your lean body mass. Subtract your body fat percentage from your current weight. For example, if you weigh 160 pounds and have 20% body fat, your lean body mass is 128 pounds (160 x 0.8). Multiply this by 0.8 to get a daily protein goal of 102.4 grams.

This may seem like a lot, but it’s completely doable if you spread it out over your meals. If you eat three times a day, aim for about 33 grams per meal. As another example, if your ideal body weight is 135 pounds, your protein requirement would be 108 grams. If you split it into two meals, it will be 54g per meal. For reference, 1 ounce of steak contains about 7 grams of protein, so a 5-ounce steak contains 35 grams of high-quality protein.

For children, the average intake is about 5 to 10 grams per meal, while 20 grams per meal is usually sufficient for young adults. For most normal-weight adults, the minimum intake needed to stimulate muscle protein synthesis is 30 g per meal. To find your personal protein sweet spot, consider factors such as age, activity level, and overall health.

Quality and Timing Matter: Optimizing Protein Intake

When it comes to protein intake, quality and timing are as important as quantity. Protein quality is sometimes expressed using the Digestive Essential Amino Acid Score (DIAAS), which measures the systemic bioavailability of essential amino acids in a particular food, meal mix, or supplement.

While most animal food sources provide good quality protein (DIAAS ≥100), whey falls into the high-quality category (DIAAS = 75-99). Leucine content is a key factor in protein quality as it stimulates muscle protein synthesis through activation of specific signaling pathways. To maximize muscle health, some experts recommend eating 25 to 30 grams of high-quality protein with at least 2.5 grams of leucine at each meal.¹²

Eating patterns are also important. Current recommendations encourage older adults to distribute their protein intake evenly across meals rather than concentrating it all at once. Additionally, consuming protein-rich meals in close proximity to your exercise routine, especially resistance training, improves muscle anabolic response and supports overall muscle health.¹³

Optimizing protein intake is important, but it’s only one piece of the puzzle when it comes to maintaining muscle health and vitality as you age. Other factors, including physical activity, overall diet quality, and gut microbiota diversity, are also associated with muscle strength and sarcopenia. A holistic approach to healthy aging is best for preserving muscle mass and function.