Why ‘old people smell’ happens — and the superfood you can eat to help prevent it

There are few odors more immediately recognizable and absolutely off-putting than “old people smell.”

Eau du elderly is characterized by top notes of mothballs and wet cardboard coupled with basement, expired canned goods and dead leaves.

Long thought to be an inevitable, olfactory consequence of aging, a longevity expert explained how the smell develops — and how one superfood can help banish it.

“Old people smell comes from lipid peroxidation on top of the skin. And if you don’t have enough antioxidants, that smell builds up, and because we don’t get a lot of cellular turnover as we age, it lingers,” Leslie Kenny, founder of Oxford Healthspan and certified Bulletproof coach, told The Post.

Kenny likens lipid peroxidation to the body rusting.

“It’s a whole body thing,” she explained. “The smell comes from a compound called 2-nonenal. It’s basically sebum that has rusted.”

Our skin’s natural antioxidant defenses decline with age. This results in increased oxidation of skin lipids and the production of 2-nonenal, a byproduct of the breakdown of omega-7 fatty acids on the skin’s surface.

Kenny maintains that, unlike body odor, old people smell cannot be disguised or washed away.

“You can’t mask it with perfume. The perfume simply layers on top of it, and it gives it a sort of musty smell,” she said.

“You can’t get rid of it through bathing more because the cells are not turning over rapidly enough, and the lipid fats are not so easy to break down, so the scent will still be there.”

The scent-sible solution to senior stank? “What you want to do is get rid of it from the inside out.”

Kenny explains that nutrition, specifically a diet dense with mushrooms, is key to this inside-out approach to staving off the scent.

Mushrooms are packed with the amino acid ergothioneine, a powerful antioxidant with anti-inflammatory properties that stops lipid peroxidation before oldie odor can accumulate.

Ergothioneine can reportedly make you smell fresh and think straight, as research suggests that diets rich in mushrooms can cut the risk of cognitive impairment in half.

Mushrooms are also an excellent source of spermidine, an organic compound that activates autophagy, the regenerative process that removes damaged cell components and recycles them to support cellular renewal.

Autophagy plays a critical role in slowing aging, protecting against disease, maintaining metabolic efficiency and mitigating mature muskiness.

Kenny notes that while all mushrooms aid and abet smelling more like a spring breeze than a caved-in root cellar, shiitake and oyster shrooms are the best bet for nutrient delivery.

According to the expert, the lipid peroxidation that causes old people smell is the stank result of two conspiring conditions: hormonal drops and a lack of cellular turnover.

“As our hormones go down, that smell is more likely to build up, and as we age, we don’t get a lot of cellular turnover, so that smell lingers for long term,” she said.

With ergothioneine halting lipid peroxidation and spermidine supporting autophagy, Kenny calls mushrooms “the perfect food to eat to combat this smell.”

Kenny told The Post that mushrooms are a preventative and curative medicine.

“As we go through perimenopause and menopause, we want to try to include more ergothioneine-rich foods like mushrooms to prevent the onset of that smell,” she said.

“And if you are older and you want to get rid of the smell, mushrooms are a great choice because, again, they’ve got the spermidine that’s going to help with the faster cell turnover.”

In addition to helping us smell more like spring chickens than old crows, mushrooms have been shown to slow cancer progression, lower blood pressure, improve insulin resistance, shield against brain damage and help keep bones healthy.

Other research has found a link between eating mushrooms and a lower risk of prostate cancer and breast cancer.

The University of Texas MD Anderson Cancer Center notes that mushroom extracts have routinely complemented cancer care in Japan and China because they are rich in vitamin D, which is critical for the immune system.