Who of the following is most likely to be deficient in vitamin C?

October 15, 2025 •

3 min read

According to the NIH, certain groups of people are far more likely to experience vitamin C inadequacy than others, even in developed countries. The question of who of the following is most likely to be deficient in vitamin C depends heavily on lifestyle, health status, and access to a nutritious diet.

Quick Summary

This article details the primary risk factors for vitamin C deficiency, highlighting vulnerable populations such as smokers, the elderly, and individuals with restrictive diets or chronic health conditions.

Key Points

Smokers are at high risk: Due to increased oxidative stress from tobacco smoke, smokers require significantly more vitamin C and have lower absorption rates.
The elderly are vulnerable: Low appetite, restrictive diets, and poor access to fresh food make older adults, particularly those in institutions, susceptible to deficiency.
Restrictive diets increase risk: People who avoid fruits and vegetables due to preference, allergy, or food faddism often have inadequate vitamin C intake.
Chronic conditions deplete reserves: Diseases like severe malabsorption, certain cancers, and kidney disease increase the body's need for or decrease its absorption of vitamin C.
Alcohol abuse impairs intake: Chronic alcohol consumption leads to poor overall nutrition, replacing nutrient-dense foods and hindering absorption.
Infants on boiled milk are at risk: Evaporated or boiled cow's milk lacks sufficient vitamin C, which is destroyed by heat.

Understanding Vitamin C Deficiency

Vitamin C, or ascorbic acid, is an essential nutrient that the human body cannot produce on its own. It is crucial for collagen synthesis, immune function, and antioxidant protection. While severe deficiency (scurvy) is rare in developed countries, inadequate intake is not uncommon. Identifying those most at risk is the first step toward prevention and healthy living.

Smokers and Exposure to Secondhand Smoke

People who smoke tobacco have one of the highest risks of vitamin C deficiency. The chemicals in cigarette smoke significantly increase the body's oxidative stress, which in turn depletes vitamin C levels. To counteract this damage, smokers require approximately 35 mg more vitamin C per day than non-smokers. Exposure to secondhand smoke also lowers vitamin C concentrations in the body, placing passive smokers at a higher risk. This increased need, coupled with often poorer dietary habits, makes smokers a prime candidate for deficiency.

The Elderly and Institutionalized Individuals

Older adults, especially those living alone or in institutional settings, often face a higher risk of malnutrition and, consequently, vitamin C deficiency. Factors contributing to this include a lack of access to fresh produce, low appetite, dental issues that affect food intake, and reliance on limited 'tea and toast' style diets. In many cases, institutionalized elderly individuals have been found to have significantly lower vitamin C status compared to their free-living counterparts.

Individuals with Restrictive Diets

Whether by choice or necessity, individuals on highly restrictive diets are at a substantial risk for low vitamin C intake. This includes:

Food faddists: People following extreme or unbalanced eating patterns that eliminate entire food groups, particularly fruits and vegetables.
Picky eaters: Children or adults with a very limited variety of foods they will consume.
Individuals with food allergies: People with severe, multiple food allergies may unintentionally restrict their intake of vitamin C-rich foods.
Infants fed evaporated or boiled milk: Cow's milk contains very little vitamin C, and heating it further destroys the vitamin. Breast milk and modern infant formulas are fortified and provide adequate amounts.

People with Alcoholism or Substance Use Disorders

Chronic and excessive alcohol consumption is a major risk factor for vitamin C deficiency. Alcoholism often leads to poor overall nutrition, as alcoholic beverages replace more nutrient-dense foods in the diet. Furthermore, alcohol can interfere with nutrient absorption and increase the body's requirements for certain vitamins.

Individuals with Chronic Health Conditions

Certain medical conditions can either increase the body's need for vitamin C or reduce its ability to absorb it, leading to a higher risk of deficiency. These conditions include:

Malabsorption disorders: Crohn's disease, celiac disease, and severe intestinal malabsorption.
Kidney disease requiring hemodialysis: The dialysis process filters water-soluble vitamins, including vitamin C, from the blood.
Certain cancers and chemotherapy: The disease process and treatment can reduce appetite and increase the body's nutritional needs.
Type 1 diabetes: Individuals with this condition may have increased vitamin C requirements.
Hyperthyroidism: An overactive thyroid can increase the body's metabolic rate and demand for nutrients.

A Comparison of Deficiency Risk

To better illustrate the variance in risk, consider a comparison between a heavy smoker and an individual with a healthy, varied diet.


Feature	Heavy Smoker	Health-Conscious Non-smoker
Dietary Intake	Often poor, with lower consumption of fresh fruits and vegetables.	Varied, includes daily servings of vitamin C-rich produce.
Bodily Demand	Increased significantly due to oxidative stress from smoke.	Standard daily requirement (90mg for men, 75mg for women).
Absorption Rate	Decreased due to smoking.	Optimal, assuming no underlying health issues.
Risk Level	High risk due to increased need and lower intake.	Low risk due to balanced diet and no extra demand.

Conclusion: Who is most likely to be deficient in vitamin C?

Of the various groups susceptible to deficiency, heavy smokers are arguably the most likely to experience a vitamin C inadequacy under normal circumstances. Their constant exposure to oxidative stress from tobacco smoke directly depletes the body's vitamin C stores and increases the daily requirement by an additional 35 mg, often on top of an already poorer diet. While other groups like the elderly or those with chronic illness face significant risks, the direct, constant, and measurable impact of smoking on vitamin C levels makes it a uniquely potent risk factor. Addressing this particular lifestyle choice can have a profound impact on an individual's vitamin C status and overall health.

For more detailed information on vitamin C requirements and risk factors, consult the Office of Dietary Supplements at the National Institutes of Health.

Frequently Asked Questions

Early signs of vitamin C deficiency include fatigue, general weakness, irritability, vague muscle and joint aches, and lethargy.

Smokers need an additional 35 mg of vitamin C per day compared to non-smokers to compensate for the depletion caused by oxidative stress.

Yes, vitamin C is critical for collagen formation, which is a major component of bone tissue. Deficiency can lead to weak, brittle bones and an increased risk of fracture.

Conditions that increase risk include malabsorption disorders (like Crohn's), end-stage renal disease requiring dialysis, certain cancers, and hyperthyroidism.

Symptoms of severe deficiency, or scurvy, typically appear after months of a daily vitamin C intake of less than 10 mg.

While older adults can be at higher risk due to diet, appetite, and other health issues, it is not universal. Free-living elderly who maintain a balanced diet can have adequate levels.

The best way is to eat a balanced diet rich in fresh fruits and vegetables daily, as the body cannot store large amounts of vitamin C.