Spicing up taste for smell-loss sufferers: Capsaicin boosts salt perception and flavor

By Tarun Sai LomteReviewed by Benedette Cuffari, M.Sc.Jun 21 2023

A recent study posted to the medRxiv* preprint server evaluates how capsaicin influences the perception of saltiness of foods in individuals with smell loss.

Study: More spice, less salt: how capsaicin affects liking for and perceived saltiness of foods in people with smell loss. Image Credit: joel bubble ben / Shutterstock.com

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Improving taste with no sense of small

People with loss of smell often complain of a lack of flavor perception and decreased eating pleasure. In an effort to regain flavor and enhance the palatability of food, many people will incorporate more salt, spices, or hot sauce into their meals.

In fact, the average sodium intake among this patient population is between nine and 12 g/day, which exceeds the five g/day recommendation by the World Health Organization (WHO). Thus, compensatory strategies to improve flavor without negatively affecting health should be introduced for people with loss of smell.

Previous studies have shown that capsaicin increases the taste intensity of salt in those with an ordinary sense of smell. Adding capsaicin to foods to improve flavor and liking of foods could help avoid excess salt intake in people with smell loss; however, this has yet to be investigated.

About the study

In the present study, researchers evaluate eating behaviors, sodium intake, and whether capsaicin improves salt taste sensitivity in individuals with loss of smell. Individuals between 18 and 65 years of age with hyposmia or anosmia for 12 weeks or less from the greater Philadelphia area were recruited for the current study, which was conducted between October 2021 and September 2022.

People with congenital anosmia were excluded. Participants visited the Monell Chemical Senses Center for test sessions on sensory evaluations of model tomato soups and other foods.

Study participants were given 12 soup samples that were consumed in random order at two-minute intervals. Taste intensity and liking were self-rated. Pasta and chocolate samples were also provided, following which the participants self-rated the taste intensity and liking of these foods.

After the first test session, study participants completed a questionnaire on eating behaviors pre- and post-loss of smell. Twenty-four-hour urine samples were also collected to measure sodium levels.

Before each session, individuals were trained to use the labeled hedonic scale to rate sample liking. Comparatively, the general labeled magnitude scale was used to rate flavor intensity, taste qualities, and spiciness.

Study findings

Thirty-three participants with an average age of 47 were included for analysis, 23 and 10 of whom had hyposmia and anosmia, respectively. Additionally, 11 individuals with hyposmia self-reported experiencing parosmia.

About 88% and 85% of the study cohort were female and White, respectively. The average duration of smell loss was three years from various causes.

Significantly more participants preferred salty foods, and fewer individuals preferred fatty foods after losing the sense of smell. However, there were no differences in the preference for sweet, bitter, and spicy foods. Around 43% of participants indicated gaining weight after losing the sense of smell, while 30% reported weight loss.

About 58% and 63% of individuals reported increased intake of spicy foods and salt post-smell loss, respectively, with 70% reported using more herbs and spices. The mean sodium intake was 2.9 g/day. Participants rated soups with low (0.0003 g/L) or moderate (0.0006 g/L) capsaicin as spicier and more flavorful than soups without capsaicin.

Soups with moderate capsaicin were rated spicier and more flavorful than those with low capsaicin. Soups with regular sodium quantity were rated sweeter, saltier, more umami, less bitter, and more flavorful than those with lower sodium. Soups with moderate levels of capsaicin were rated less sweet, more bitter, and more umami than soups without capsaicin.

Regular sodium soups were liked more than those with reduced sodium. Capsaicin did not affect soup liking.

Chocolate and pasta samples with low (0.17 g) or moderate (0.33 g) levels of cayenne pepper were rated spicier and more flavorful than those without the spice. Consistently, pasta and chocolate with moderate spice levels were rated spicier and more flavorful than those with low levels of spice.

Pasta samples were rated less bitter, saltier, less sweet, more sour, and more umami than chocolate. Food samples with moderate spice levels were rated more sour than those without spice.

Pasta was liked more than chocolate, with moderate levels of spice in pasta increasing its liking. Younger individuals, males, and participants with anosmia had higher ratings of food liking than older individuals, females, and people with hyposmia.

Conclusions

Individuals with a loss of smell consumed more herbs, salt, spices, and spicy foods, with capsaicin increasing salt taste intensity and food flavor.

Taken together, the study findings indicate that incorporating more spice into food products could be a valuable strategy to improve flavor, salt taste intensity, and liking of foods, particularly in individuals with a loss of smell. Future studies are needed to determine whether this strategy could reduce sodium consumption and enhance diet quality.

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.