Cut out tomatoes to avoid body odour. That’s the message from a chemist and physician, who had a personal reason for embarking on a ground-breaking study of a process worth around £640 million to the UK deodorant industry.
In a paper published in the journal Medical Hypotheses, Dr Charles Stewart explains how body odour is determined partly by genetics which control the degree of sweating from the armpit glands and the amount of sweat, and by the presence of bacteria such as Corynebacterium that live on the skin.
As he explained to the Mail: ‘We have long known that these bacteria turn armpit sweat into foul odours – by breaking down proteins in the sweat into smelly compounds.’
Some people are fortunate that their genes stop their armpit sweat glands working in this way, so they do not smell. ‘This is common in the Far East, especially Korea. However, most Westerners sweat from their armpits, and may smell.’
But he believes it’s not just genetics and poor hygiene that are to blame. It’s tomatoes.
Dr Stewart has worked for more than two decades with drug companies developing treatments for skin conditions ranging from eczema to cancer. His tomato discovery was prompted by the 2007 heatwave – when colleagues would open windows wide if he was there.
Embarrassed, he knew the problem was his body odour, but he couldn’t shift it despite using generous quantities of soap. Then he noticed that tomato stalks are filled with an oil that smells like sweat and wondered if they were the culprit.
The oil contains terpenes, substances that give fruit and vegetables such as oranges, lemons and hops their smell and flavour. When Dr Stewart stopped eating tomatoes his problem disappeared. In 2013, he added tomatoes and other terpene-rich foodstuffs to his diet.
In one experiment he ate four large tomatoes and found that the under-arm odour had reappeared, despite sticking to the same personal hygiene regimen. The odour lasted for seven days. ‘It is really surprising the odour can last so long, after one meal,’ says Dr Stewart. ‘But it means people who eat tomatoes and tomato products always have a risk of smelling when they sweat.’
While he doesn’t know how much they’d need to eat a day for this effect, as little as 50 to 100g might be enough. He is yet to investigate if cooking the tomatoes makes a difference.
He believes the reason terpene-containing compounds may play a role in body odour is due to the way they are broken down by enzymes, producing chemicals that act on the antioxidant compound lycopene, found in tomatoes. This in turn produces other chemicals known to contribute to how the body smells.
A report published in the journal Experimental Dermatology in 2012 concluded that certain chemicals linked to body odour were caused by specific foods. The report analysed previous studies showing that a compound in fish oil was linked to body odour.
Dr Stewart says that one outcome of his work is that cutting out tomatoes and paying attention to good personal hygiene could eliminate need for deodorants.