What determines your taste?
Picture this: you’re at a crowded party and after having a go at it on the dance floor you step aside for a minute to recuperate. During this time, you realize this familiar peckish feeling creeping up on you. You decide to walk over to the most exciting part of the room- the snack table. Sprawled across the massive table are mini pizzas, pretzels and cupcakes. You’re now faced with a decision. A decision that will inevitably be made by years of environmental, psychological and genetic factors all culminating to this very moment when you ask yourself: sweet or salty?
As a person with a strong affinity to the sweeter tastes in life, I found it only fitting to write my first blog post exploring the reason why some people prefer sweet snacks, whereas others prefer salty snacks.
Humans are able to recognize five tastes: sweet, bitter, sour, salty and unami( savoury) . Food preference and intake is influenced by sweet and bitter taste. For example, studies show that preference for sweet and high-fat food decreases with increased perception of bitter tastes.
The term ‘sweet tooth’ refers to an individual who prefers sweet tastes, implying they differ from those who do not prefer sweet tastes. However, it has been noted that sweet perception also varies between individuals and even in the same individual over time. Several factors apart from taste receptors are at play to determine the human ‘sweet tooth’ such as genetics, nutrition, body mass index, psychology and hormones.
The main receptors identified for sweet and unami taste are encoded by three TAS1R genes found on chromosome1p36. In taste receptor cells found in the tongue, two proteins, namely T1R2 and T1R3, combine to from a ‘sweet’ receptor. The associated genes for these receptors are TAS1R2 and TAS1R3 respectively. DNA variants of these genes are shown to have influenced a person’s response to sweeteners, increasing its eligibility to be factor that also accounts for the inter-individual differences in sweet perception.
A study found that a minor allele in a FGF21 variant was significantly associated with higher carbohydrate and lower protein and fat intake. It further showed that the carbohydrate preference was specifically sugary products. This means a different version of a gene in people can steer them towards wanting more sugary treats. These findings were also consistent with animal studies that show FGF21 signaling is associated with the reward centers in the brain. Refined sugar can offer a stronger reward and can increase cravings for sugary products.
Apart from genetic differences and taste receptors, behaviours encouraging a walk on sweeter side of life may be created by our psychological need for the rewarding effects of sugar. Sweets may alleviate depression, even premenstrual symptoms and offer relief from the cravings for other drugs because sweet taste releases opiates into the blood. The pleasant feeling, easy digestion and positive effect on mood all contribute towards steering behavior toward sugar consumption. However, the want to consume sugars can also be influenced negatively by fear of over-consumption of sugars can lead to obesity and type 2 diabetes. Another negative factor I am sure we have all been reminded about as children is the effect sugar will have on our dental health.
If not sweet, why salty?
Reasoning for why certain people prefer salty tastes over sweet ones seems to have a more physiological reason. A study showed that a child who was unable to make the aldosterone, which is a hormone that regulates sodium in the body, continued to excrete sodium. As a result of having low sodium levels in the body, the child developed a sodium appetite followed by great thirst due to the large amounts of sodium he was digesting. His appetite and thirst was so powerful it caused the young man to develop odd psychological tendencies to get salt and water, such drinking ocean water. His motivation became so overpowering that his first word was ‘salt’. No, I did not make that up. It was taken from a scientific paper. This might be an extreme case but nevertheless, it is a striking example of how sodium deficiency drives a sodium appetite. Of course, many of us who prefer salty snacks do not form part of that extreme but sodium depletion could play a physiological role in the choices we make.
Another factor to consider is your stress level. Stress can cause an imbalance in the sodium regulatory pathways which can lead to one developing salt cravings. It has also been shown that children born from mothers who experienced a sodium depletion during pregnancy show greater salt intake in adulthood. Also, babies how endured bouts of salt loss due to vomiting or diarrhea also showed a higher salt intake during their teenage years.
The next time you’re faced with a table of tasty treats, or simply craving a sweet or salty snack, take a moment to recognize what factors could be driving your decision.
References:
Frayling, T.M., Beaumont, R.N., Jones, S.E., Yaghootkar, H., Tuke, M.A., Ruth, K.S., Casanova, F., West, B., Locke, J., Sharp, S. and Ji, Y., 2018. A common allele in FGF21 associated with sugar intake is associated with body shape, lower total body-fat percentage, and higher blood pressure. Cell reports, 23(2), pp.327-336.
Grimm, E.R. and Steinle, N.I., 2011. Genetics of eating behavior: established and emerging concepts. Nutrition reviews, 69(1), pp.52-60.
Hurley, S.W. and Johnson, A.K., 2015. The biopsychology of salt hunger and sodium deficiency. Pflügers Archiv-European Journal of Physiology, 467(3), pp.445-456.
McCallister, M.,2020, Salty or sweet: what you crave may tell you something.Living safer, viewed 29 March 2020, <https://www.livingsafer.com/salty-or-sweet-what-you-crave-may-tell-you-something/>
Nutrition , 2017, 3 Reasons You Crave Sweet or Salty Foods. Health Essentials from Cleveland Clinic, viewed 30 March 2020, <https://health.clevelandclinic.org/3-reasons-you-crave-sweet-or-salty-foods/>
Reed, D.R. and McDaniel, A.H., 2006, June. The human sweet tooth. In BMC Oral health (Vol. 6, No. 1, p. S17). BioMed Central.
Sweeney.E.,2019,Genetics Are Partly To Blame For Your Food Cravings,Huffpost, viewed 29 March 2020, <https://www.huffpost.com/entry/genetics-food-cravings_l_5c657877e4b0aec93d3c35e3>
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