Protein has been all over social media in recent years, especially in relation to perimenopause. While I agree that protein is one of the most important nutrients, not all protein is created equal. A spoonful of peanut butter and an egg both count as “protein”, they are not available to your body in the same way.

Many women assume they’re eating enough protein because the grams add up, when their body can actually only use part of it.

I should also clarify that I don’t recommend peanut butter. Peanuts grow underground, where they’re prone to moulds that produce mycotoxins such as aflatoxin, which can harm the liver and initiate brain fog and other symptoms. I frequently see aflatoxin on my clients’ test results.

Protein quality: complete or incomplete?

Protein is the raw material for almost everything your body builds and repairs, from muscle, bone and skin to enzymes, immune cells and brain messengers. Perimenopause asks a lot of the body, and from midlife we lose muscle and bone more easily, so the demand is high.

Protein is made of amino acids. Nine are essential, which means they must come from food. We need all nine together to build protein. If one is in short supply, your body can’t use the rest to build protein. They’re broken down and burned for energy instead, of no real benefit.

• Animal protein (meat, fish, eggs and dairy) is complete: it has all nine in the right balance.
• Most plant protein is low in one or two. Unless your diet is carefully designed with the right mix, such as beans with rice, you won’t get enough of every essential amino acid. Soy is the main exception.*

You can see the difference in studies: beef, pork and eggs supported more protein building in the body than the same “portion” of beans, peanut butter, tofu or nuts, which provided no more than half the protein. Even tofu performed more like beans than meat. Yet US guidelines count 1 egg, 1 tablespoon of peanut butter and ¼ cup of beans as equal “protein foods”, which one researcher called a “false equivalence”. The UK’s Eatwell Guide has the same blind spot, grouping pulses, nuts, eggs, fish and meat together.

Your ability to absorb protein matters

Eating protein is only half the story: your body then has to digest and absorb it. Plant protein is harder to absorb, because many plant foods contain natural compounds, such as phytates and lectins, that reduce how much protein and minerals we take up.

Digesting protein starts in your stomach. Stomach acid unfolds the protein and switches on pepsin, the enzyme that begins breaking it down. Enzymes from your pancreas then finish the job in your small intestine, and a healthy gut lining absorbs the amino acids. Stomach acid and enzymes often decline with age, stress and some medications, such as antacids. If you have gut health issues, from low stomach acid to bloating or another condition, you may absorb much less of the protein you eat. Feeling heavy or bloated after protein-rich meals can be a sign.

How protein is prepared matters too. Gentle, slow cooking, as in stews and broths, makes protein easier to digest, while charring and very high heat can reduce its quality. For plant foods, soaking, sprouting and fermenting help reduce these compounds.

Your liver needs quality protein

Your liver uses amino acids such as glycine, cysteine, methionine and taurine to clear used hormones and toxins. Your body can make some of these, but in a demanding time like perimenopause it may not make enough.

This matters in perimenopause, when many women experience heavy, flooding periods. These are often linked to high oestrogen, which your liver has to process and remove. If it isn’t keeping up, oestrogen may build up. If you take HRT, your liver processes those hormones too.

Feeling full and calm

You’ll know you’ve had enough good-quality protein when you feel full and calm. Animal protein supports a calmer mind in two ways:

• Steadier blood sugar. Complete protein keeps you full and helps keep your blood sugar steady. When it dips, your body releases adrenaline and cortisol to correct it, which can feel just like anxiety: a racing heart, jitteriness, or waking in the night. Raised cortisol is linked with more troublesome hot flushes and poorer sleep.
• Key nutrients. Low B12, iron and zinc are linked with anxiety and low mood, and all three are best absorbed from animal foods.

Large studies have found that people who eat animal protein report less anxiety and depression, on average, than those who avoid it.

If you often feel anxious or on edge, it’s worth looking at the quality of the protein on your plate.

Your brain needs it too

Brain fog, low mood and poor focus are common in perimenopause. Your brain makes the messengers that steady your mood, focus and sleep from the amino acids in protein, and animal foods supply them most reliably. As psychiatrist Dr Georgia Ede puts it: “The brain needs meat.”

If you eat mostly plants

In my clinical and personal experience, it is incredibly challenging to support the health of women who are vegan, and even vegetarian. I respect your choice, but I’ve seen how often it leaves women depleted, and how this can affect their health, fertility and menopause transition.

Plant foods such as beans, lentils and seeds are still valuable. To get the most from them, combine legumes with grains, nuts or seeds across the day, such as dal with rice or hummus with seeded crackers, and aim for a little more protein overall. Nut butters are best seen as an extra: at around 8 g a serving, they aren’t a protein meal.

At every meal, ask yourself: “where is my protein?”

Your protein needs are individual to you

There’s no single number that’s right for every woman. Together, we can assess and improve your nutrition, support your gut health so your body can make the most of what you eat, and guide you through the perimenopause transition. Book a consultation, in person in Petersfield or worldwide through video call.

Magda Jenkins is a registered Nutritional Therapist and Naturopath (mBANT, CNHC, ANP) specialising in women’s health.

*What about soy? Most soy grown worldwide is genetically modified and sprayed with glyphosate, and soy protein isolates (found in protein bars, powders and meat substitutes) are usually extracted with the chemical solvent hexane. Dr Georgia Ede also points out that soy isoflavones can slow down the enzyme your thyroid needs to make its hormones, and that cooking doesn’t change this. She lists soy among the foods most likely to affect thyroid function. If you do eat soy, choose organic, traditionally fermented forms such as tempeh, miso and natto.

References

• Matthews, J.J. et al. (2025) ‘Understanding dietary protein quality: digestible indispensable amino acid scores and beyond’, The Journal of Nutrition, 155(10), pp. 3152–3167.
• Park, S. et al. (2021) Anabolic response to protein food sources, The Journal of Nutrition.
• Harcombe, Z. ‘Meat is a natural part of a healthy diet’. Talk at the Hybu Cig Cymru conference, reported by Meat Management.
• Ede, G. (2024) Change Your Diet, Change Your Mind. Balance.
• Ede, G. ‘Foods that cause hypothyroidism’. Diagnosis Diet.
• Martin, C.G. (2021) ‘False equivalence or fake news: is a peanut really an egg?’, The Journal of Nutrition. doi: 10.1093/jn/nxab051
• NHS. ‘The Eatwell Guide’. nhs.uk
• Dobersek, U. et al. (2021) ‘Meat and mental health: a meta-analysis of meat consumption, depression, and anxiety’, Critical Reviews in Food Science and Nutrition.