A new study from the University of Otago, Christchurch, has found a strong connection between low vitamin C levels and increased body weight.
This discovery raises concerns as obesity rates continue to rise worldwide.
The research, published in Critical Reviews in Food Science and Nutrition, suggests that current vitamin C intake recommendations may be too low for many people, especially those who are overweight.
Are Current Vitamin C Guidelines Outdated?
Professor Anitra Carr, the lead researcher and director of the Nutrition in Medicine Research Group, explains that existing vitamin C recommendations are based on a 70-kilogram (154-pound) male, with only a small allowance for weight differences.
However, with global body weights increasing, many people are not getting enough vitamin C under these outdated guidelines.
For example, in New Zealand, the World Health Organization (WHO) recommends 45 milligrams of vitamin C per day, one of the lowest recommendations in the world. However, Professor Carr’s research suggests that for every additional 10 kilograms (22 pounds) of body weight, a person needs 17 to 22 milligrams more vitamin C to maintain healthy levels.
Large-Scale Data Supports the Findings
The study analyzed data from two major sources:
- The 2017-2018 US National Health and Nutrition Examination Survey (NHANES), which included 2,828 adults.
- The 1993-1997 European Prospective Investigation into Cancer (EPIC)-Norfolk study, with 20,692 participants.
Results showed that only about two-thirds of participants reached an “adequate” vitamin C level by following the standard recommended daily allowance. When intake was adjusted for weight, only one-third to half of participants had sufficient vitamin C.
Why Does Obesity Affect Vitamin C Levels?
Scientists believe that obesity changes how the body processes vitamin C. Several factors may contribute to lower vitamin C levels in people with higher body weight:
- Inflammation and oxidative stress: Obesity causes chronic low-grade inflammation, which increases oxidative stress. This may lead to a faster breakdown of vitamin C.
- Higher vitamin C turnover: Larger body size means vitamin C is used up more quickly.
- Increased risk of certain diseases: Obesity raises the risk of type 2 diabetes and non-alcoholic fatty liver disease, both of which are linked to lower vitamin C levels.
How to Increase Vitamin C Intake
To address this issue, researchers suggest increasing vitamin C intake through dietary sources or supplements.
Professor Carr offers simple dietary solutions:
- Apples contain about 10 mg of vitamin C, so adding an extra apple or two daily can help.
- Oranges provide 70 mg, making them a good option for those needing a higher dose.
- Kiwifruit has 100 mg, making it one of the best natural sources.
For those taking supplements, she recommends checking labels, as some multivitamins contain very low doses of vitamin C that may not be enough to meet increased needs.
The Bigger Picture: Health Risks of Vitamin C Deficiency
Beyond preventing scurvy, vitamin C plays a role in heart health, immune function, and disease prevention. Studies suggest that low vitamin C levels are linked to an increased risk of:
- Heart disease and cancer
- Infections and slow wound healing
- Depression and fatigue
With obesity rates rising, ensuring proper vitamin C intake could be an important factor in maintaining overall health and reducing disease risks.
This study highlights the need for revised vitamin C intake recommendations that account for body weight differences. As obesity continues to increase worldwide, updating these guidelines could help ensure better health for millions of people.
For those concerned about maintaining a healthy weight and getting enough nutrients, small dietary changes—such as increasing vitamin C-rich foods—could make a big difference.
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