Researchers at the Oregon State University in Corvallis believe they have identified the sixth primary taste, ‘starchy’, in addition to the five primary tastes of salty, sweet, sour, bitter and umami. Umami is a taste that is synonymous with monosodium glutamate, or MSG, and was added just seven years ago.

Study co-author Juyun Lim from Oregon University says, “Every culture has a major source of complex carbohydrate. The idea that we can’t taste what we’re eating doesn’t make sense.” Thus, the researchers felt that the previous list was still missing a major component of the dietary habits seen across the world.

‘Starchy’ as a taste in its own right

Their preliminary research suggests that we can, in fact, also taste carbohydrates, making ‘starchy’ a flavour in its own right. This discovery might explain the global popularity of carbohydrates, and why they appear to be so irresistible. From rice in Asia to pasta, bread and potatoes in Europe and the Americas – it is universally understood that carbohydrates are a big part of the everyday diet.

Complex carbohydrates are composed of chains of sugar molecules that are strung in long and complex chains. They are found in peas, beans, grains, and vegetables. Simple and complex carbohydrates are processed by enzymes in our saliva into glucose, which is the body’s main energy source. It is initially thought that we taste carbohydrates via the indirect tasting of glucose.

The tongue distinguishes ‘starchy’ from mere sweetness

The team tested their hypothesis by giving volunteers a range of different carbohydrate solutions, and they were able to identify the taste as ‘starchy’; although exactly how they described that taste was found to vary.

“Asians would say it was rice-like, while Caucasians described it as bread-like or pasta-like. It’s like eating flour,” as Juyun Lim explains.

Researchers initially suspected that the test subjects had misidentified starchy as a sweet taste, but even with their sweet receptors blocked, they could identify this starchy flavour. This suggests that we have the ability to taste carbohydrates before they are broken down into sugar molecules.

Michael Tordoff at Monell Chemical Senses Center in Philadelphia is convinced by the evidence published, calling it impressive and adding that “it will surprise a lot of people.”

Stringent criteria to qualify as a primary taste

However, before qualifying as a new primary flavour, this new taste must meet a strict list of criteria. Flavours must be recognisable, have their own set of tongue receptors, trigger a useful physiological response, and be useful for us.

Currently, starch does not qualify as the researchers have yet to identify specific starch receptors on the tongue. As for the usefulness of starch, researchers argue that as it is a valuable slow-release energy source, humans would find it useful to clearly identify.

Carbohydrates are not for all

Amylase is the enzyme, found in our saliva, responsible for breaking down complex carbohydrates into simple carbohydrates and sugars. Production of amylase is not natural for all; it requires the gene AMY1. This would mean some of us would be able to break down complex carbohydrates before it reaches our stomach, and some are unable to.

It is proposed that it is in our genetic disposition that some might be addicted to carbohydrates due to the abundance of amylase, and some would need to reduce their intake of carbohydrates, due to a deficiency in the presence of amylase, to prevent the onset of Type 2 Diabetes.

Sharon Moalem, a neurogeneticist and evolutionary biologist has a quick and easy homemade self-test that allows one to assess their optimal carbohydrate intake level. Just take a coin-sized piece of raw potato, and time the duration it takes to detect a change in taste in the potato. The faster the taste changes, the more carbohydrates your genes can handle in your daily diet.

Growing global obesity rates still a problem

Research in Journal of Sports Medicine last year showed that the overconsumption of carbohydrates and sugary substances are the chief cause of obesity, as opposed to a sedentary lifestyle.

In Malaysia, obesity is at all-time high with 7% of children under five labelled overweight while almost 30% of children and teenagers aged between 6 and 17 were either overweight or obese. Additionally, obese Malaysians make up 17.7% of the population while those who are categorised as overweight make up 30%, according to the most recent National Health and Morbidity Survey 2015.

In Singapore the rising rate of obesity is a cause of concern; as 12% of schoolchildren were labelled obese in 2014, up from 10% in 2000, as reported by the Ministry of Education.

Perhaps more startling is that 34% of Singaporeans aged 24 to 35 in 2016 are projected to be diabetic by age 65, based on a study by Chia Kee Seng, the dean at the Saw Swee Hock School of Public Health.

Globally, the World Health Organisation estimates that childhood obesity will rise by 70% by 2025 to 70 million, from 42 million in 2014. MIMS


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