Tokyo, Jan 26 (IANS): The umami of "fifth taste" could have an important and beneficial role in health especially in elderly people, according to a new research.

Sweet, salty, sour, bitter and umami are the five basic tastes.

Despite the widely held belief that monosodium glutamate (MSG) is an unhealthy addition to food, researchers from Tohoku University Graduate School of Dentistry, Japan, show that the taste it triggers -- umami -- is important for health, especially in elderly people.

In a small study of 44 elderly patients, the researchers showed that some elderly patients suffer a loss of the umami taste sensation and that all of the patients studied complained of appetite and weight loss, resulting in poor overall health.

Umami taste receptors also reportedly exist in the gut, suggesting that the umami taste sensation functions in nutrient sensation and modulating digestion in the gut, which could be important for maintaining a healthy daily life.

The researchers suggest that diseases suffered by elderly patients and side effects from their medications could cause taste disorders and reduced salivation.

They also found that treatment to improve salivary flow had a beneficial effect on the patients' taste sensations and could help patients with reduced umami sensitivity.

The study also found that 'kokumi' substances, which modify flavour, could improve the taste of low-fat foods.

'Kokumi' substances, as found in garlic, onions and scallops, are known to enhance basic tastes when combined with other flavours, despite having no taste themselves.

The paper appeared in the open-access journal Flavour.