A closer look at zinc
For years, people living with smell loss have wondered whether taking zinc might help recovery. Older studies suggested it probably didn’t, but more recent work has added new context and continues to shape how we think about zinc’s role.
One study from 2023, led by Japanese researcher Dr Eri Nori and colleagues, explored whether zinc levels in the blood are linked to how well people can smell. This matters because most earlier research tested zinc supplements without first checking if people actually had low zinc levels.
What the researchers found
The study included 90 people with smell loss caused by infections, head injuries, medication side effects, neurological problems, or no known reason (called idiopathic cases). Researchers measured each person’s serum zinc levels and compared the results with standard smell tests such as the T&T olfactometer and the Open Essence test.
Participants with zinc levels below 60–70 µg/dL performed noticeably worse on smell tests. The link was especially strong for those with idiopathic smell loss. This suggests that zinc deficiency may worsen smell problems in people whose loss of smell has no clear cause.
Why this matters
Past clinical trials concluded that zinc supplements did not make much difference to smell recovery overall. However, when people are grouped according to their actual zinc status, a different picture emerges. Those who start out with low zinc may have more to gain than those whose levels are normal.
A later study, published in 2024, found that when zinc levels were restored to a healthy range (above 70 µg/dL), participants tended to do better on smell tests than those who remained zinc deficient. This adds weight to the idea that maintaining normal zinc levels may support recovery and improve the efficacy of smell training.
What to do if you have smell loss
If your loss of smell is idiopathic, you might consider asking your GP for a blood test to check your zinc level. The NHS provides general reference ranges for adults: around 9–20 µmol/L, depending on age and sex. These can vary slightly between NHS Trusts, so it’s worth confirming what’s used in your area.
If your level is low, your GP can advise on diet or supplements. Foods naturally rich in zinc include:
- nuts and seeds
- beans and lentils
- dairy and eggs
- wholegrains
- meat and seafood
A note of caution
The Mayo Clinic advises that adults generally need 8–11 mg of zinc per day, depending on age and sex. The upper safe limit is 40 mg per day. Taking too much zinc can cause nausea or stomach upset, and over time can affect the absorption of other minerals such as copper and iron.
It’s always best to stay within recognised limits and to follow medical advice when considering supplements.
Key Takeaway
Low zinc levels may play a part in smell loss, especially when the cause is unknown. While more research is needed, checking your zinc status with your GP is a simple step that could help you better understand your sense of smell and support recovery.
