Introduction
Diabetes mellitus and its symptoms were first described in ancient Egypt, around 2000 B.C.1 Over the past few decades, patients with Type 2 Diabetes mellitus have more than doubled globally, making it one of the most important public health challenges worldwide. Type 2 diabetes is strongly associated with obesity. The prevalence of obesity-related diabetes is expected to double to 300 million by 2025.2 The connotation ‘diabesity’, highlights the fact that the majority of diabetic individuals are overweight or obese.3, 4 An increased BMI increases the individuals' mortality risk 7-fold.5 According to the WHO, obesity is the largest global chronic health problem.6 It is estimated that by the year 2030, 60% of the world's population will be overweight or obese.7, 8
An impairment of gustatory function in T2DM patients has been reported in earlier studies. Duration of the disease and poor glycaemic control,9, 10 and obesity might play a causal factor for the same.
Table 1
Concentrations of the taste stimuli used (g/ml) and the allotted scores
Materials and Methods
This was a cross-sectional study comprising a sample size of 40. Patients aged 25 to 50 years with T2DM < 5 years duration with HBA1C ≤ 7 were recruited from a tertiary care hospital for the research. They were divided into 2 groups, Group I- with normal weight (BMI of 18.5 to <25) and Group II with grade 1 obesity (BMI of 30 to < 35). The duration of the study was 2 months.
Exclusion criteria comprised of subjects with a past or present history of psychiatric disorders, recent respiratory tract infection, hypothyroidism, chronic kidney or liver disease stage, on sedatives, antibiotics, antiepileptic medications, alcoholics, smokers, pan, tobacco and other substance abusers, pregnant or breastfeeding women and subjects who have contacted COVID-19 in the past six months. Consent was obtained from the Institute’s Review Board. HBA1C levels, anthropometric measurements and BMI were calculated. The triple drop test was used to evaluate gustatory function. Five different concentrations of sweet, salty, sour and bitter tastants were used in dilutions of 50% steps using sucrose, sodium chloride, citric acid, and quinine hydrochloride respectively (Table 1). Samples were presented as drops on the anterior part of tongue, swished in the mouth for ~5 seconds and spit out. Subject was asked to rinse the mouth thoroughly with water in between. Scoring was done depending on the identification of concentrations, “1” being highest, “5” being the lowest concentration.
Result
The mean taste scores for the tastants: sweet, salty, sour and bitter in Group I were 3.9± 0.96, 4.75± 0.55, 4.75± 0.55 and 3.24± 1.12 respectively, while the mean taste scores in Group II were 2.34± 1.3, 3.32± 1.5, 4± 0.725 and 2± 1.17 respectively. A significant difference (p < 0.05) was noticed in the taste scores amongst the two groups. This signifies that obese patients with T2DM respond to a higher concentration for the tastants as compared to non-obese T2DM patients. (Table 2)
Discussion
This study provides an assessment of taste sensations perceived by T2DM patients in the Indian population and it supports the findings of previous studies. In a study by Shreya Khera et al it was observed that T2DM patients showed a higher threshold to sweet, salt, sour and bitter tastes.11 Manley KJ et al concluded in their study that a significant impairment in sweet taste sensation occurs in diabetic patients.12
Taste impairment observed in obese T2DM patients can have a negative impact on health and can further deteriorate diabetes. Hypogeusia may cause the already obese diabetics to consume more food and indulge more in hedonic eating. Obesity itself is a risk factor for many diseases esp. in diabetic individuals and it should not progress further. Utilized to advise them to use ingredients that enhance flavours but have low: herbs, spices, potassium chloride, non-nutritive sweeteners and sweet enhancers, in order to limit sodium and sugar intake.
Conclusion
Our study concludes that gustatory impairment for the tastants – sweet, salty, sour, and bitter was observed in obese Type 2 Diabetes mellitus patients having the disease for less than 5 years, though maintaining a fair glycaemic control. This may affect their choices of food items like preference for sweet- tasting food which can exacerbate hyperglycaemia and aggravate obesity. Hypoguesia may also lead to greater intake of salty diet which can escalate the risk of hypertension, renal and heart diseases. Obesity itself is a risk factor for many diseases esp. in diabetic individuals and it should not progress further. It would further decline the quality of life (QOL). Knowledge about Hypogeusia in obese diabetics may be used in dietary counseling. Further, studies with larger sample size should be undertaken to understand how exactly obesity impairs taste sensation.
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