Millets (pearl and finger) as nutritional interventions for COVID 19 with focus on Zimbabwe: mini review

Figures & data

Table 1. Summary of nutritional composition of millets and the role of nutrients in COVID-19 prevention and treatment

Nutrient category	Nutrient/mineral	content		Important function in the body	Roles on immune system/ treatment /prevention of COVID-19	References
		Finger millet	Pearl millet
Proximate		(g/100 g)
	Protein	7.7	11.6 –11.8	Growth, repair of worn-out tissues, production of enzymes, hormones and antibodies.	Key in immune system modulation, antibody and enzyme production thereby preventing infection e.g. SARSCoV-2 infection.	Kumar et al, 2018 Naja and Hamadeh, 2020. Junaid et al, 2020.
	Fat/ lipids	1.8	4.5 - 5.0	Provision of energy, energy store, cushioning of delicate organs, Polyunsaturated fats lower blood cholesterol level.	Polyunsaturated fatty acids (PUFA) are central in the maintenance of immune cell functions The derivatives of PUFA, Omega-3 and omega-6 are pro- and anti-inflammatory hence being screened as potential COVID-19 treatment interventions.	Ahmed et al., 2013. Sarita and Singh, 2016. Rao et al., 2017. Ramashia et al., 2019. Farag et al., 2020.
	Carbohydrates	75.0- 83.3	67- 67.5	Soluble polysaccharides (SP) provide energy slowly digestible starch, resistant starch and Complex unavailable polysaccharides are critical in preventing and managing diabetes and hyperlipidemia	Important energy sources that support the immune system highly critical in immunity as they prevention decrease of number of cells conjoint to apoptosis. Some reduces underlying conditions e.g. diabetes and hyperlipidemia which increase the severity COVID-19	Ahmed et al., 2013. Dayakar et al., 2017. Rao et al., 2017. Ramashia et al., 2019. de Morais, 2020.
	Dietary fiber	15- 22.0	11.3	Reduced risk of inflammatory bowel disease, constipation and bloating.	Reduces underlying conditions e.g. diabetes which increase the severity COVID-19
Phenolic compounds and polyphenols	Ferulic and Phytic acid	-	-	Have key function in decreasing body cholesterol. Restricts damage of tissues and promotes tissue regeneration.	Reduces underlying conditions e.g. diabetes which increase the severity COVID-19	Sarita and Singh, 2016 Chandra et al., 2018
	Tannins, phytates, and phenol	-	-	Essential in treating metabolic problems and degeneration. Enzyme inhibition e.g. α-amylase thereby lowering Hyperglycemia after eating Prevents incidences of cardiovascular diseases and tumor development, reduces chances of diabetes and hypertension	Reduces underlying conditions e.g. diabetes which increase the severity COVID-19	Siwela et al., 2007 Thilagavathi et al., 2015 Kumari et al., 2017
Micronutrients	Minerals	(mg/ 100 g)
	Zinc	2.3	3.1	Promotes the proliferation of immune cells, prevents respiratory infections. Acts as an antioxidant thereby protecting the body against bacterial and viral infections.	Critical in the adaptive and innate immune cells pathway modulation. Reduces RNA virus multiplication e.g., SARS-CoV-2. Inactivates ACE2 receptors responsible for SARS-CoV-2 entry into host cells.	Ali et al., 2003. Oliveira et al., 2018. Nairz et al., 2018. Read et al., 2019
	Iron	3.3-14.89	8.0	Important in enhancing the immune system, reducing chances of anaemia and recurring acute respiratory tract infections. Inhibits progressive inflammation and prolonged hospital stay	Contribute critically to immune development and upregulation of the immune response. Mediates in generation of hydroxyl radicals, which are central in stimulating the differentiation of T lymphocytes involved in elimination of viruses and bacteria	Ganz and Nemeth, 2015. Maywald et al, 2017. Mishra and Patel, 2020. Aman and Masood, 2020. Calder, 2020
	Magnesium	78-201	137	Blood pressure reduction, reduced asthma incidences and the chances of heart attack.	Involved in the development of immune responses against viral infections Involved in production of antibodies, CD8+ and CD4+ adherence.
	Vitamins	mg/100g
	A (Retinol)	6.0	-	Significant for epithelial cell integrity and maintains healthy stomach, intestines and respiratory system.	Anti- inflammatory and improves differentiation of T helper 2 and immune responses. Promotes interleukins 4 production (which decreases vulnerability of cells to SARS-COV-2 and down-regulates angiotensin-converting enzyme). Significant for immune capacity of the mucosa hence reduces viral infection.	Brown and Noell, 2015 Hemilä, 2017. Carr, 2017 Erkelens and Mebius, 2017. Aman and Masood, 2020. Mishra and Patel, 2020. Arshad, 2020. Calder, 2020. Oliveira et al., 2018.
	Vit B1(Thiamine)	0.2- 0.48	-	Plays a central role in muscle contraction, conduction of nerve signals and keeping nervous system, digestive system and skin healthy	Involved in the production of antibodies and in cellular immune defense It is critical in cellmetabolism and in the maintenance of immune homeostasis
	Niacin	1.0-1.30	-
	Vitamin C	≤1.0	-	Required in the formation proteins used to make skin, tendons, ligaments, and blood vessels Has an antioxidant activity hence prevent cancer, heart disease, and conditions including arthritis.	It activates cellular function of innate and adaptive immune system. It is critical in antibodies, lymphocytes, and macrophages function. Stimulates of signalling molecules and interferon release, hence providing defense against viruses. Is a weak anti-histamine which provides relief from flu-like symptoms.

Figure 1. Theoretical framework of the role of millets in COVID-19 treatment and prevention.

Figure 2. Theoretical framework of the role of millets in reducing severity of underlying conditions associated with COVID-19.

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