Part 2: Protein’s Pro-Aging Power

Written by Laura Tarbell, Board Certified Wellness Coach, Functional Nutrition Practitioner, Precision Nutrition Level 1 Coach, Clean Health Level 3 Personal Trainer, Advanced STOTT Pilates Instructor, IFBB Pro Bikini Competitor, and Contest Prep Specialist

Photography by Paul Buceta

Hair & Makeup by Monica Kalra

PART TWO of a six-part series dedicated to learning how to navigate midlife hormonal and metabolic chaos, with vitality, to live your menopausal years to the fullest.

Protein is a fundamental macronutrient that plays a critical role in the structure, function, and regulation of the human body. Antibodies that inactivate pathogens as part of your immune system are a type of protein. Many hormones, including insulin and thyroid hormones which help regulate your blood glucose and metabolism, and impact growth hormone secretion and bone health, are made from the amino acids provided by protein. The brain uses protein-rich foods to produce neurotransmitters like epinephrine, norepinephrine, serotonin, and dopamine, all of which are directly linked to neurological development, sleep, and mood. Every tissue in your body is made up of protein, accounting for approximately 40 percent of your body composition. 

With all of this, along with the body’s constant repair and rebuild cycles, your body has a high demand for protein. If there’s not enough protein coming in, your body will default to survival of your organs, and performing functional operations versus supporting external goals like muscle growth and performance. By creating a nutrition plan with a muscle health focus that is high in protein, you’ll be able to meet both your biological needs as well as optimize for your fitness and body composition goals. 

When we also factor in the significant hormonal shifts women experience starting in their 30s and 40s—studies support the need to boost protein intake in midlife. 

One of the most significant shifts during this time is the loss of the anabolic (muscle-making) stimulus that estrogen provides. With age, we also become more anabolic resistant (AR)—defined as the body’s reduced ability to build and repair muscle tissue in response to an anabolic stimuli such as resistance training and protein intake. The graph shows the difference in the shaded area between muscle protein synthesis (MPS) in the young versus the elderly, aged 60+.⁽¹⁾ Because of this, perimenopausal women not only need to change their training (addressed in Master Midlife Part 1), they also need to beef up their protein game (pun intended) in order to keep their muscles strong and healthy.  

Unfortunately, that’s not all. Sarcopenia completes the perfect storm for muscle loss potential. Sarcopenia is the involuntary loss of skeletal muscle mass and strength, which starts around age 30 and proceeds at a rate of ~0.6% annually for both men and women. Therefore, sufficient protein intake for females is critical in order to provide the necessary amino acids, aka, “the building blocks” required for repairing and rebuilding muscle tissues after the muscle protein breakdown that occurs during training. 

As always, the quality of protein matters too. Leucine, along with isoleucine and valine, is one of the three branched-chain amino acids (BCAAs). Out of all the amino acids, leucine is the most potent activator of protein synthesis and affects muscle hypertrophy. Cells are able to sense leucine levels and, in response, turn on protein synthesis via an enzyme protein called mTOR, the master-regulator of protein synthesis. Studies show a “consumption of 3-4 grams of leucine is needed to promote maximum protein synthesis.”⁽²⁾ You can achieve this by consuming 30 grams or more of protein at a time. Great food sources of leucine include salmon, chicken, lentils, soy beans, eggs, and peas to name a few. 

As mentioned, protein is important for mood regulation as well. Research published in American Journal of Clinical Nutrition highlights that protein-rich diets can positively influence the synthesis of serotonin and dopamine, neurotransmitters that play a vital role in mood regulation. This dual benefit of preserving muscle mass and enhancing mood further supports the importance of incorporating enough protein into diet as a supportive strategy for women navigating perimenopause.

So what’s the right amount of protein and when should it be consumed? Even if you’re not protein deficient right now, let’s make sure you’re protein optimized. 

The current RDA for protein for women is 46 grams, a target based on old-school nitrogen balance developed for animal agriculture. However, new recommendations for women say to aim for 1.7 to 2.4 grams (g) of protein per kilogram (kg) of body weight per day [1 kilogram = 2.2 lbs, so to determine your weight in kgs from lbs, divide by 2.2]. For active women 40+ with diminishing estrogen, a slightly higher range of 2.2-2.4 grams of protein would be more appropriate for muscle preservation and overall health. This means if we follow the current International Society of Sports Nutrition (ISSN) recommendations, stating female athletes should aim for a caloric intake of at least 45 calories per kg of lean body mass per day,⁽³⁾ then a 150-pound woman with 25 percent body fat should consume 2,300 calories with a protein intake range of 150-163 grams. 

Previously, research suggested dividing protein evenly throughout the day to maximize the cycle of muscle protein synthesis. But a recent study reveals that consuming increasingly larger amounts of protein post workout leads to a corresponding increase in protein absorption, muscle protein synthesis rates, and overall whole-body protein balance.⁽⁴⁾ These findings challenge the long-held belief that there is a limit to how much protein can be effectively utilized in one sitting, with excess being wasted or used for energy, or stored as fat rather than muscle synthesis. This is great news for perimenopausal and menopausal women because if you’re consistently short on protein, post workout is the best time to really ramp up your intake. 

Overall, protein impacts everything from muscle to mood to metabolism. In your perimenopause years and beyond, protein becomes even more vital to ensure longevity, metabolic function, and quality of life. Prioritize it.

Sample Nutrition Plan*

To hit appropriate calories for a 150-lbs active female who trains mid-morning with macro targets of 163 g Protein (26%), 207 g Carbs (45%), and 75 g F (26%).*

References 

1. Breen, L., Phillips, S.M. Skeletal muscle protein metabolism in the elderly: Interventions to counteract the ‘anabolic resistance’ of ageing. Nutr Metab (Lond) 8, 68 (2011). https://doi.org/10.1186/1743-7075-8-68 2. Stark, M., Lukaszuk, J., Prawitz, A. et al. Protein timing and its effects on muscular hypertrophy and strength in individuals engaged in weight-training. J Int Soc Sports Nutr 9, 54 (2012). https://doi.org/10.1186/1550-2783-9-54
3. Sims ST, Kerksick CM, Smith-Ryan AE, Janse de Jonge XAK, Hirsch KR, Arent SM, Hewlings SJ, Kleiner SM, Bustillo E, Tartar JL, Starratt VG, Kreider RB, Greenwalt C, Rentería LI, Ormsbee MJ, VanDusseldorp TA, Campbell BI, Kalman DS, Antonio J. International society of sports nutrition position stand: nutritional concerns of the female athlete. J Int Soc Sports Nutr. 2023 Dec;20(1):2204066. doi: 10.1080/15502783.2023.2204066. PMID: 37221858; PMCID: PMC10210857. 4. Trommelen J, van Lieshout GAA, Nyakayiru J, et al. The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans. Cell Rep Med. 2023;4(12):101324.