Hong Kong dermatologists and longevity experts reveal the root causes of age-related body odour and the surprising dietary solution hiding in plain sight
Many of us have noticed it—that distinct, musty scent lingering in an elderly relative’s bedroom or clinging to their clothing. Often dismissed as a lack of hygiene, this phenomenon, colloquially known as “old person smell” or “加齡臭” (ageing odour), is actually a natural biological process that begins as early as 40.
But what exactly causes this change, and more importantly, how can it be managed effectively?
The Chemical Culprit Behind the Scent
According to Taiwanese dermatologist Dr Xu Changjie, who appeared on the health programme “祝你健康” (Wishing You Health), the root cause of age-related body odour lies in a chemical reaction within our skin. As we age, the unsaturated fatty acids in our sebum undergo oxidation, producing a compound called “2-nonenal” —the primary substance responsible for that characteristic oily, grassy smell.
This isn’t a matter of poor personal hygiene. Rather, it’s a physiological shift that affects both men and women. While men often experience more pronounced odour due to higher levels of androgens stimulating sebum production, women are not exempt. After menopause, declining oestrogen levels relative to androgens can trigger the same issue.
The Five ‘Oil Hotspots’ That Redirect Washing Habits
Many older adults avoid soap, fearing it will dry out their already fragile skin, and opt for water-only rinses. Dr Xu warns that this approach is ineffective, as 2-nonenal is a fat-soluble substance that water alone cannot remove.
The key is to focus on five specific areas where sebum accumulates most heavily:
- The scalp
- Behind the ears
- The back of the neck
- The chest
- The upper back
These “oil hotspots” require targeted cleansing with appropriate soap or body wash. Additionally, Dr Xu notes that old, repeatedly worn undergarments can absorb and retain these odorous oils over years. Regularly replacing underwear and undershirts is essential for odour control.
The Antioxidant Approach: Why Mushrooms Are a Game-Changer
Since oxidation is the core mechanism behind age-related body odour, consuming antioxidant-rich foods can help reduce the production of 2-nonenal from the inside out. Dr Xu recommends increasing intake of vitamin C, vitamin E, green tea polyphenols, and berries. However, he cautions that pungent ingredients like spring onions, ginger, and garlic—while healthy in other respects—may actually intensify body odour.
Oxford longevity expert and founder of Oxford Healthspan, Leslie Kenny, advocates a more surprising solution: mushrooms. She identifies two key compounds in fungi that make them exceptionally effective:
- Ergothioneine: A unique natural amino acid with powerful antioxidant and anti-inflammatory properties that inhibits lipid peroxidation, directly reducing 2-nonenal production.
- Spermidine: A natural polyamine that activates autophagy—the cellular process of cleaning out damaged components and regenerating newer, healthier cells.
Research suggests that consuming approximately 300 grams of mushrooms per week can not only improve body odour but also significantly lower the risk of mild cognitive impairment and prostate cancer.
Practical Takeaways for Hong Kong Readers
For immediate action:
- Use soap or body wash on the five key “oil hotspots” during showers.
- Replace old undergarments that may harbour trapped odours.
- Incorporate mushrooms into meals 3–4 times per week.
Mushroom varieties to prioritise:
- White button mushrooms (excellent for ergothioneine and spermidine)
- Shiitake (rich in polysaccharides for immunity)
- King oyster mushrooms (high in fibre for gut detoxification)
- Enoki (contains amino acids that boost metabolism)
- Maitake or porcini (high antioxidant content for anti-ageing)
Simple recipes to try:
- Creamy mushroom soup
- Black pepper mushroom rice (a KFC-inspired favourite)
- Mushroom fettuccine in white sauce
- Salmon and mushroom risotto
As Hong Kong’s population ages, understanding the science behind these natural bodily changes can help reduce stigma and improve quality of life. The good news is that with simple dietary adjustments and smarter hygiene habits, managing age-related body odour is entirely achievable—and deliciously so.