Genotypic variation in Na, K and their ratio in 45 commercial cultivars of Indian tropical onion: A pressing need to reduce hypertension among the population

Hira Singh; Mauro Lombardo; Abhishek Goyal; Amrender Kumar; Anil Khar

doi:10.3389/fnut.2023.1098320

Genotypic variation in Na, K and their ratio in 45 commercial cultivars of Indian tropical onion: A pressing need to reduce hypertension among the population

Front Nutr. 2023 Feb 21:10:1098320. doi: 10.3389/fnut.2023.1098320. eCollection 2023.

Authors

Hira Singh^{1

2}, Mauro Lombardo³, Abhishek Goyal⁴, Amrender Kumar⁵, Anil Khar²

Affiliations

¹ Department of Vegetable Science, Punjab Agricultural University, Ludhiana, India.
² Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Open University, Rome, Italy.
³ Department of Cardiology, Dayanand Medical College and Hospital, Ludhiana, India.
⁴ Agricultural Knowledge Management Unit, ICAR-Indian Agricultural Research Institute, New Delhi, India.
⁵ Division of Vegetable Science, ICAR-Indian Agricultural Research Institute, New Delhi, India.

Abstract

The intake of diets with higher sodium (Na) and lower potassium (K) has been considered a leading factor for the development of hypertension (HTN). Majority of junk, processed and packaged food have higher Na contents. To counter the effects of diet on HTN, the identification of high K/Na ratio plant-based food is needed. Among fruits and vegetables, onion could be the ideal option since it contains high K content. Keeping this in mind, 45 commercially well adapted short day Indian onion cultivars were evaluated for K and Na content and their ratio to isolate suitable cultivars to prevent HTN in the Indian population. The data suggested wide variation among the genotypes for K, Na, and K/Na ratio ranging from 490.2 ± 17.0 to 9160.0 ± 96.7 mg/kg on dry matter basis, 52.7 ± 3.0 to 458.2 ± 61.7 mg/kg on dry matter basis and 3.1 ± 0.7 to 109.5 ± 17.3, respectively. The K content was recorded as significantly highest in the yellow-coloured bulb variety "Arka Pitamber" (9160.1 ± 96.7) followed by Pusa Sona (7933.2 ± 292.8). On the other hand, minimal K was assessed in the white-coloured bulb variety "Agrifound White" (490.3 ± 17.0) followed by Udaipur Local (732.9 ± 93.4). Twelve cultivars exhibited > 7000 mg K content, while nine cultivars recorded < 1500 mg. On the contrary, Na was recorded as significantly highest in the dark-red-coloured bulbs and the lowest in white bulbs. Furthermore, it was determined that there was a more than 35-fold difference observed between the highest (109.5) and lowest (3.1) K/Na ratio in the bulbs of tested cultivars. Cluster analysis revealed three major groups comprising of 23, 13 and 9 genotypes. This information could form the base for public health, food and onion researchers to design suitable cultivars to prevent HTN as a population-wide approach. The next century is going to be food-based for the amelioration of human diseases in a sustainable way without any after-effects on the human body.

Keywords: Allium cepa L.; cardiovascular diseases; hypertension; onion bulbs; potassium; potassium/sodium ratio; sodium.

Grants and funding

Authors are thankful to the ICAR-Indian Agricultural Research Institute, New Delhi for providing financial support and conduct of the research program of the PhD student, HS. The research work was partially funded by the NAHEP-CAAST programme of Indian Council of Agricultural Research.