Why eating more protein is essential for women over 40

Protein is found in muscle, the heart, immune system, enzymes, hormones, skin, hair, nails. These proteins are made from chains of amino acids that are constantly being broken down and rebuilt into new, more effective proteins. When proteins are broken down into their constituent amino acids, not all of the amino acids can be reused and these are broken down and eliminated via the kidneys in urine. This creates is a constant need for protein to replace the lost amino acids. Muscle acts as a reservoir of amino acids. If protein intake is low or there is an extended period without eating protein, the body will break down muscle tissue to provide the amino acids needed to rebuild proteins in the body.

According to the protein leverage theory (Raubenheimer & Simpson), humans are driven to eat until all of their protein needs are met. When the protein content of the diet is diluted by an increased intake in fats and carbohydrates, more food is consumed in order to meet those same protein requirements. This can lead to an excess energy intake and subsequently weight gain.

Our food has undergone significant protein dilution due to the introduction and growth of mass produced, hyper palatable, processed foods. These foods not only contain much less protein than would have occurred in the diet of our ancestors but also the use of highly palatable combinations of sugar and fat along with umami flavours drives us to choose foods with a lower protein content.

During perimenopause there is an increased need for protein as protein breakdown increases whilst protein synthesis decreases creating an overall net loss of protein.

This gradual loss of muscle mass and strength is a condition known as sarcopenia. For women over 40, this decline in muscle mass can lead to reduced physical function and increased risk of falls and fractures. Dietary protein provides essential amino acids necessary for muscle protein synthesis and repair, making it a key factor in preserving muscle mass and function.

Hormonal changes during perimenopause, can lead to a decrease in bone density and an increased risk of osteoporosis. Protein contributes to the formation of collagen, a structural protein essential for bone and joint health.

As well as maintaining bone and muscle mass, protein-rich foods can promote a feeling of fullness and satiety which helps to control appetite, which in turn makes it easier to manage weight. Additionally, protein has a higher thermic effect, meaning it requires more energy to digest and metabolize than fats or carbohydrates.

Neurotransmitters are made from the amino acids found in protein and so protein intake is essential for the production of key brain chemicals. The hormonal changes that occur during perimenopause impact the neurotransmitter function in the brain. This can be exacerbated by nutrient deficiencies, including low protein intake.

This combination of factors mean that perimenopausal women have an increased demand for protein. The recommended dietary allowance (RDA) for protein is 0.8 grams of protein per kilogram of body weight. For the average sized woman this works out at about 40g of protein a day. However, the RDA for a population is the absolute minimum intake needed to avoid hair loss issues or major skin issues. It is not representative of the amount needed for optimum health.

The European Society of Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) recommends an optimal protein intake of up to 1.2g/kg of ideal body weight whilst the PROT_AGE study recommends up to 1.5g/kg for those over 60.

To meet their protein needs, it is essential that women over 40 incorporate a variety of protein sources into their diets. Lean meats, poultry, fish, dairy products are all excellent choices.