Research Blog
Vitamin C is an essential micronutrient required for several bodily functions and is a primary antioxidant. Its functions include preventing oxidative damage and reducing atherosclerosis and cardiovascular risk. While most mammals produce vitamin C, humans cannot and must obtain adequate vitamin C from their diet. Fresh fruits and vegetables are significant sources of vitamin C.
Vitamin C insufficiency is a major public health concern in developed areas, including the USA, New Zealand, Japan, Russia, and elsewhere.
A retrospective cross-sectional study evaluated cardiovascular risk factors and vitamin C intake in a subtropical region of Taiwan. Results revealed insufficient vitamin C (ascorbic acid) levels were associated with significantly higher triglycerides above 150 mg/dL (1.69 mmol/L, homocysteine above 10 umol/L, hs-CRP 1 mg/dL or above, and lower HDL-C 46 mg/dL (1.19 mmol/L) or below.
Both homocysteine and CRP are markers of inflammation, associated with oxidative stress, and contribute to atherosclerosis. Homocysteine levels above 10 umol/L and hs-CRP levels of 1 mg/L or higher are independent cardiovascular risk factors.
Fasting plasma vitamin C levels were categorized into:
Deficiency 2.0 mg/L (0.2 mg/dL, 11.36 umol/L) or below
Subdeficiency 2.1 - 6.0 mg/L (0.21-0.6 mg/dL, 11.92 - 34.07 umol/L)
Suboptimal 6.1 - 8.8 mg/L (0.61 - 0.88 mg/dL, 34.64 - 49.97 umol/L)
Optimal 8.9 - 15 mg/L (0.89 - 1.5 mg/dL, 50.53 – 85.17 umol/L)
Supraphysiological Above 15 mg/L (1.5 mg/dL, 85.17 umol/L)
Many individuals had insufficient vitamin C levels despite the region being referred to as the “fruit kingdom,” suggesting dietary intake of ascorbic acid must be carefully planned to reach therapeutic levels in the blood.
The content of vitamin C varies by season, with the following levels per 100 grams of fruit:
- Guavas (Autumn) – 137.9 mg
- Papayas (Autumn) – 58.3 mg
- Pomelos (Autumn) – 54.5 mg
- Lychees (Summer) – 52.3 mg
- Oranges (Winter) – 41.2 mg
- Mangos (Summer) – 22.7 mg
- Pineapples (Spring) – 12.0 mg
- Bananas (Spring) – 10.7 mg
- Pitayas (Autumn) – 5.3–6.3 mg
- Pears (Summer) – 4.6 mg
- Grapes (Summer) – 3.8 mg
- Apples (Winter) – 2.9 mg
Optimal Takeaways
- Vitamin C plays an essential role in the primary prevention of cardiovascular disease.
- Vitamin C protects LDL and HDL cholesterol from oxidative damage that can significantly increase cardiovascular risk.
- Insufficient vitamin C levels were associated with significantly higher triglycerides, homocysteine, hs-CRP, and lower HDL-C.
- Lower vitamin C levels are associated with higher homocysteine and vice versa.
- Vitamin C supplementation can reduce elevated C-reactive protein, triglycerides, and LDL-C. 500 mg daily for at least four weeks can significantly reduce triglyceride and LDL-C levels.
- Vitamin C insufficiency was associated with obesity, male gender, younger age, and winter or spring months.
- Ultimately, vitamin C levels should be maintained above 8.9 mg/L (0.89 mg/dL, 50.53 umol/L) and ideally above 15 mg/L (1.5 mg/dL, 85.17 umol/L) for those at the highest cardiovascular risk.
Reference
Lin, Yao-Tsung et al. “Prevalence and Predictors of Insufficient Plasma Vitamin C in a Subtropical Region and Its Associations with Risk Factors of Cardiovascular Diseases: A Retrospective Cross-Sectional Study.” Nutrients vol. 14,5 1108. 6 Mar. 2022, doi:10.3390/nu14051108 This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
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