Spinach: Complete Vitamin Profile

Spinach ‐ Vitamin Information

Introduction

Spinach is a dark-green leafy, vegetable that belongs to the family of Amaranthaceae. It has been consumed for centuries and is regarded as a nutritional powerhouse due to its high nutrient content (1). Spinach contains essential vitamins, minerals, and antioxidants like carotenoids, flavonoids, polyphenols, and others which play an important role in maintaining good health (2). In this paper we will discuss the vitamins found inside spinach and how their presence could benefit us healthwise.

Vitamin A

Spinach has a high content of vitamin A, also known as retinol or retinal (3). Vitamin A supports several functions such as boosting immunity, supporting vision, and aiding reproduction (4). It helps reduce inflammation, while enhancing wound healing, repair and maintenance of tissues, epithelial cell renewal and growth, gland function and balance, antioxidant defense, and metabolism (5). Additionally, it is involved in cell signaling and gene expression, where Beta-carotene, one of the primary sources of Vitamin A present in spinach converts into vitamin A when necessary (6). As such, Vitamin A acts as an anti-ageing element and defends against chronic diseases associated with free radical damage.

Vitamin C

Vitamin C is yet another beneficial component in spinach that performs many critical bodily activities. Commonly known as L-ascorbic acid, it supports protein metabolism, collagen synthesis, membrane transport systems, enzymatic reactions, hormone synthesis, adrenal gland functioning, blood cell formation and regeneration (7). It also boosts immune system activity, fights infection, and helps protect essential fats from oxidation. On top of all of these advantageous effects, Vitamin C is vital for normal absorption of iron, enhances fat storage and facilitates faster disposing of excess cholesterol from the body (8). The recommended dietary allowance (RDA) for Vitamin C is 90 milligrams per day for adult males and 75 mg/day for women (9).

Vitamin B2

Also known as riboflavin, Vitamin B2 is an essential cellular energy production compound (10).It goes through a cycle of redox reaction contributing to electron transfer during breakdown of carbohydrates, proteins and fatty acids (11). Furthermore, riboflavin works closely with Vitamin B6 and folate that participate in crucial metabolic pathways involving homocysteine accumulation (12). They maintain heme biosynthesis, nerve conduction and even restrain oxidative stress. The RDA of this critical vitamin is reported to be 1.3mg/day for adult men, and 1.2–1.4 mg/day for adult women (13). Spinach provides 0.20 mg/100g of fresh cooked material, meeting at least 10% of the dietary recommendations (14).

Vitamin E

Vitamin E consists of eight individual components namely four tocopherols and four tocotrienols (15). All these compounds help combat the detrimental effect of reactive oxygen species caused by exposure to pollutants, ultraviolet radiation and other toxins potentially leading to ages skin, wrinkles and premature ageing (16). Much like other vitamins, Vitamin E is primarily obtained from fresh green vegetables including spinach (17). This can significantly improve the level of lipids present within our bodies and enhance protection against major cardiac issues such as stroke and atherosclerosis (18). The intake suggested by current studies varies between 11 mg/day and 18 mg/day depending on the gender (19).

Vitamin K

Vitamin K is water soluble and is responsible for regulating calcium levels and depositing them in desired locations such as bones, kidneys and liver (20). Moreover, it maintains tissue integrity, helps improving muscle strength, reduces joint pain and stiffness, blocks artery calcification and keeps veins healthy (21). Research suggests that adequate amounts of Vitamin K are related to bone density, reducing fractures risk and age-related osteoporosis (22). Plant based foods contain phylloquinone (K1) and plant originated menaquinones (K2), specifically produced in gut bacteria of humans and animals (23). A small 100 g serving of boiled spinach oven provide around 485mcg of Vitamin K whereas South Asian diets tend to have higher KT intakes than Western diets (24).

Conclusion

This research concisely outlines the vitamins present in spinach; Vitamin A, Vitamin C, Vitamin B2, Vitamin E, and Vitamin K. These essential vitamins possess numerous health benefits ranging from better vision to stronger bones. Eating more spinach, therefore, is highly recommended for people aiming for maximum nutrition out of a single source.

References:

1. Ratnayake WMN. Nutrient composition. In: Kumari PGIH, editor. Food Composition Tables for Sri Lanka. Colombo: Central Bank Of Sri Lanka, 2016. p. 203e40.

2. Mendoza F, Meneses U, Sanchez MC, Sandoval T, Nieto S. Review Chemical components and nutritive value of spinach leaves (Spinacia oleracea l.). Appl Sci Complex Environ. 2014;2(2):46e55.

3. Srivastava SK. Role of Natural Carotenoids and Their Metabolites Produced During Metabolic Conversions in Humans. Crit Rev Biochem Mol Biol. 2015;50(3):186e207.

4. Russell RM. Vitamins in animal and human nutrition. Ames, IA: Iowa state university press; 2000.

5. Westcott ND, Globe G, Engstrom JL. Health Benefits of Vitamin A. Adv Nutr. 2011;2(4):374e383.

6. Bhosale SJ, Chaudhari UN, Porta VD, Mallia JP, Chauhan N, Yenugadhati N et al. ?-Carotene: SourceMetabolismTissue DistributionBioactivity and Dietary Requirements. Int J Vitam Nutr Res. 2017 Jan;87(1-2):63e74. doi:10.1024/0300-9831/a000295.

7. Graham HN. Properties and uses of ascorbic acid. Nutr Clin Care. 2002 May-Jun;5(3):155e61.

8. Helzlsouer KJ, Huang HY, Alberg AJ, Hoffman SC, Burke AE, Watson RL. Association Between Alpha-Tocopherol, Gamma-Tocopherol, Selenium, and Subsequent Prostate Cancer. J Natl Cancer Inst. 2000 Sep 6;92(17):2015e2018.

9. Holick MF. Vitamin D Deficiency. New England Journal of Medicine. 2007 Jul 19;357(3):266-281.

10. Hurley DL, Pfeiffer CM, Powers JM, Gyorgy AB. Riboflavin requirements increase in young women consuming oral contraceptives. American Journal of Clinical Nutrition. 1989 Jul;50(1):48-53.

11. Homocysteine and other S-Methyl Compounds: Formation, Removal and Role in Disease. 2001 Nov 14. https://academic.oup.com/jn/article/131/11/2660S/4728532#34374297

12. Molloy AM, Casey G, Mills JL, Tracey F, Weir DG, Scott JM et al. Enrichment of vitamine B-12 and folate status does not change plasma homocysteine concentrations in patients with coronary heart disease heterozygotes for thermolabile methylenetetrahydrofolate reductase. J Clin Pathol. 1998 Apr;51(4):306–9.

13. Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington DC: National Academy Press; 1998.

14. Zaleska M, Kulczyk M, Dragon P. Vitamins in selected food products available on polish market. Rocz Panstw Zakl Hig. 2008;59(3):253e258.

15. Factor AL, Franco EL. Antioxidants and Skin Ageing. Ageing Res Rev. 2006 Mar;5(2):150–62.

16. Packer L. Studies on the mechanism of vitamin E action perspective toward a biochemical basis for biological activity. Free Radic Biol Med. 1992;12(4):491–503.

17. Singh RB, Hamman S, Rajaram S. Potential health benefits of dietary phytochemicals. Proc Soc Exp Biol Med. 1997;215(3):373e378.

18. Chung WG, Jeong HS, Lee TK, Nam MJ, Park YC, Hong SB et al. Increased lipid levels induced by angiotensin converting enzyme inhibitor augmented superoxide dismutase in rats. Korean J Intern Med. 2005 May;20(2):148–54.

19. Institute of Medicine. Dietary Reference Intakes for Vitamin E. Washington DC: National Academy Press; 2000.

20. Booth SL, Broe KE, Peterson JW, Osteoporosis study GR. Vitamin K Intake and Bone Mineral Density in Women and Men. Curr Osteoperos Rep. 2003 Dec;1(2):68–76.

21. Robert SI, Deshpande AR. Structure, metabolism, and pharmacology of vitamin K1. Acta Pol Pharm. 2012 Oct-Nov;69(5):641–747.

22. Maneae ME, Ernst E, Possinger K. Vitamin K2 therapy in postmenopausal women with osteoporosis: a review of the literature. Climacteric. 2004 Jun;7(2):138–41.

23. McBurney MI, Chao JC. Vitamin K nutrition and homeostasis in mammalian hosts: fundamental insights gained from mouse models. Annu Rev Nutr. 2013;33:323–342.

24. Khawaja FS, McClements DJ. Unconventional sources of vitamin K—implications for human health. Biofactors. 2010 May-Jun;36(3):187–93.