Smokers have measurably higher needs for several vitamins and minerals, but the single most important supplement to consider is vitamin C. Smoking accelerates the destruction of ascorbic acid in the body, and the depletion cascades into other nutrients, particularly vitamin E. At the same time, there is one supplement smokers should actively avoid: beta-carotene in pill form, which raises lung cancer risk in people who smoke. The picture gets more nuanced from there, with vitamin D, several B vitamins, and the mineral selenium all running lower in smokers’ blood than in nonsmokers’.
Vitamin C Comes First
Smoking floods the body with free radicals and other oxidants. Vitamin C, the body’s primary water-soluble antioxidant, gets used up neutralizing those molecules. Studies consistently find that smokers have blood vitamin C levels roughly 30% lower than nonsmokers, and about two-thirds of smokers fall below the threshold considered adequate. One study found vitamin C concentrations of about 51 micromoles per liter in smokers compared with about 69 in never-smokers.1PubMed Central. Effect of smoking, smoking cessation, and nicotine patch on wound dimension, vitamin C, and systemic markers of collagen metabolism The U.S. dietary guidelines already recommend that smokers get an extra 35 milligrams of vitamin C per day beyond the standard recommendation, which brings the target to roughly 125 mg for men and 110 mg for women. Many researchers and clinicians suggest aiming higher, around 200–250 mg daily through food and supplements combined, to keep blood levels in a healthy range.
Vitamin C also does something else that matters for smokers specifically: it recycles vitamin E. When vitamin E neutralizes a free radical in cell membranes, it becomes a tocopheroxyl radical itself, essentially “spent.” Vitamin C converts it back to its active form. Research has shown that smokers lose vitamin E from their blood faster than nonsmokers, but supplementing with vitamin C slowed that loss by about 25% for alpha-tocopherol and 45% for gamma-tocopherol.2PubMed. Faster plasma vitamin E disappearance in smokers is normalized by vitamin C supplementation So adequate vitamin C does double duty: it directly scavenges oxidants and it keeps vitamin E functional longer.
The Beta-Carotene Danger
If you smoke, do not take beta-carotene supplements. This is one of the most well-established and alarming findings in supplement research. In the early 1990s, a large trial involving male smokers in Finland tested whether beta-carotene supplements could prevent lung cancer, based on the reasoning that people who ate more beta-carotene-rich foods had lower cancer rates. The result was the opposite of what anyone expected: men who took beta-carotene pills had an 18% higher incidence of lung cancer than those who did not.3PubMed. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers
A second trial, known as CARET, confirmed the danger. That trial tested beta-carotene combined with retinyl palmitate (a form of vitamin A) in over 18,000 people at high risk for lung cancer, including smokers and asbestos workers. The intervention arm showed higher lung cancer incidence and higher overall mortality, and the trial was stopped early as a result.4PubMed Central. Nested case–control study of telomere length and lung cancer risk among heavy smokers in the β-Carotene and Retinol Efficacy Trial The U.S. Preventive Services Task Force now explicitly recommends against beta-carotene supplementation for the prevention of cardiovascular disease or cancer, a recommendation driven largely by these findings in smokers.5PubMed. Vitamin, mineral, and multivitamin supplements for the primary prevention of cardiovascular disease and cancer: U.S. Preventive services Task Force recommendation statement
The mechanism likely involves how beta-carotene interacts with the chemical environment inside a smoker’s lungs. Animal research suggests that at pharmacological doses, beta-carotene interacts with tobacco smoke compounds to alter retinoid signaling pathways and generate pro-oxidant byproducts, essentially doing the opposite of what an antioxidant is supposed to do. Interestingly, when beta-carotene was tested at lower, food-equivalent doses or combined with vitamins C and E, the harmful effect disappeared or even reversed in animal models.6Taylor & Francis Online (Nutr Cancer). Beta-carotene and lung cancer in smokers: review of hypotheses and status of research The takeaway is clear: eating carrots and sweet potatoes is fine, but popping a beta-carotene pill while smoking is genuinely dangerous. Check your multivitamin label too, because many contain beta-carotene.
Vitamin D Runs Low
Smokers consistently have lower circulating vitamin D than nonsmokers. A meta-analysis pooling data from multiple studies confirmed that this gap holds regardless of age group and even among smokers who take vitamin D supplements.7PubMed Central. Smoking behavior and circulating vitamin D levels in adults: A meta-analysis Individual studies have found significantly reduced levels of both 25-hydroxyvitamin D (the form measured in standard blood tests) and 1,25-dihydroxyvitamin D (the active hormonal form), alongside suppressed parathyroid hormone.8PubMed. The influence of smoking on vitamin D status and calcium metabolism
Why smoking lowers vitamin D is not entirely settled. It could be direct biochemical interference with vitamin D metabolism, or it could partly reflect the lifestyle patterns common among smokers, such as less outdoor physical activity and different dietary habits. Regardless of the cause, the practical implication is the same: if you smoke, getting your vitamin D level tested is worthwhile, and supplementation in the range of 1,000–2,000 IU daily is reasonable if levels come back low. Vitamin D is important for bone density, immune function, and possibly mood, and smoking already damages all three of those domains through other mechanisms. One study of male stroke patients found vitamin D levels averaging about 52 in smokers compared with about 62 in nonsmokers, a meaningful gap.9PubMed. The effect of cigarette smoking on vitamin D level and depression in male patients with acute ischemic stroke
B Vitamins and DNA Damage
Smoking depletes several B vitamins, and the consequences go beyond general nutrition. Folate (B9), vitamin B6, and vitamin B12 all circulate at lower concentrations in smokers. One study found that after adjusting for diet, smokers had roughly 20% lower plasma folate, 32% lower red blood cell folate, and over 50% lower folate in their cheek lining cells compared with nonsmokers. Plasma B12 and B6 were also significantly reduced. The same study documented that smokers had about twice the frequency of micronuclei (a marker of DNA damage) in their buccal cells compared with nonsmokers.10The American Journal of Clinical Nutrition. Chronic cigarette smoking is associated with diminished folate status, altered folate form distribution, and increased genetic damage in the buccal mucosa of healthy adults
Vitamin B6 in particular has attracted attention for its relationship to lung cancer risk. A large study published in JAMA found that people with the highest blood levels of B6 had less than half the lung cancer risk of those with the lowest levels, even after adjusting for smoking intensity.11JAMA. Serum B Vitamin Levels and Risk of Lung Cancer A separate prospective study in older men reported a similar pattern: those in the highest fifth of serum B6 had about half the lung cancer risk of those in the lowest fifth.12American Journal of Epidemiology. Association of the B-Vitamins Pyridoxal 5′-Phosphate (B6), B12, and Folate with Lung Cancer Risk in Older Men And a European case-control study found that poor functional B6 status was associated with about a 25% increase in lung cancer risk.13PubMed Central. Impaired functional vitamin B6 status is associated with increased risk of lung cancer
For B12 specifically, smoking creates an unusual problem. Cigarette smoke contains hydrogen cyanide, and the cyanide binds to active forms of B12 in the blood, converting them to cyanocobalamin, which is biologically inert until the body reconverts it. Lab research has demonstrated that cigarette smoke extracts chemically transform both methylcobalamin and hydroxycobalamin into cyanocobalamin.14PubMed Central. Exploring the Impact of Cigarette Smoke Extracts on Vitamin B 12 : Insights into the Transformation of Methylcobalamin and Hydroxycobalamin to Cyanocobalamin through In Vitro Evaluation This means smokers not only have lower B12 levels but may have a higher proportion of their remaining B12 in an inactive form. Some practitioners recommend methylcobalamin or hydroxocobalamin forms rather than cyanocobalamin when supplementing B12 for smokers, since the cyano form would just add more cyanide into a system already burdened by it.
Selenium and Other Minerals
Among minerals, selenium is the one most consistently depleted by smoking. Selenium is a building block for glutathione peroxidase, one of the body’s most important antioxidant enzymes. Studies have found that smokers have significantly lower plasma selenium and lower glutathione peroxidase activity than nonsmokers.15PubMed. Effects of tobacco smoking on plasma selenium, zinc, copper and iron concentrations and related antioxidative enzyme activities A study in teenage girls who smoked confirmed the same pattern: lower selenium-dependent enzyme activity, lower glutathione reductase, and lower superoxide dismutase compared with nonsmoking peers.16Nutrition. Influence of Smoking on Markers of Oxidative Stress and Serum Mineral Concentrations in Teenage Girls in Korea
Zinc, iron, and copper do not show a consistent depletion pattern in smokers across studies. Some research shows slightly elevated copper in smokers, while zinc and iron levels tend to be similar between groups. The practical implication is that high-dose mineral supplements beyond selenium are not supported by the evidence for smokers. Brazil nuts, seafood, and whole grains are good dietary sources of selenium, and a modest supplement of 55–100 micrograms daily is reasonable for smokers who eat few of those foods.
Cadmium, Fruit, and a Hidden Benefit of Vitamin C
Tobacco smoke is a major source of cadmium exposure. This toxic heavy metal accumulates in the body over years of smoking and contributes to kidney damage, bone loss, and cancer risk. Here is where vitamin C shows yet another benefit: in male smokers, blood cadmium levels were inversely associated with fruit consumption and vitamin C intake. Smokers who ate more fruit and got more vitamin C had measurably lower cadmium in their blood.17The Journal of Nutrition. Blood Cadmium Concentrations of Male Cigarette Smokers Are Inversely Associated with Fruit Consumption Animal research has also shown that vitamins C, E, and A can reduce cadmium concentrations in organs and mitigate cadmium-induced damage across multiple organ systems.18PubMed Central. The role of well-known antioxidant vitamins in the prevention of cadmium-induced toxicity This provides one more reason for smokers to prioritize vitamin C-rich foods and supplements.
What About Multivitamins
Given the multiple nutrient depletions smokers face, you might assume a daily multivitamin would be an obvious solution. The evidence on multivitamins is surprisingly lukewarm. A systematic review of multivitamin-multimineral supplements found no clear patterns of benefit or harm by smoking status, with most risk estimates for cancer, cardiovascular disease, and death hovering near the null value.19PubMed. A systematic review of multivitamin-multimineral use and cardiovascular disease and cancer incidence and total mortality A large cohort study similarly found that multivitamin associations with mortality did not vary by smoking status.20PubMed Central. Multivitamin Use and the Risk of Mortality and Cancer Incidence The Multiethnic Cohort Study
The problem with relying on a standard multivitamin is twofold. First, most multivitamins contain only modest doses of vitamin C (often 60–90 mg), which is unlikely to close the gap for a smoker. Second, many multivitamins include beta-carotene, sometimes at substantial levels. If you choose to take a multivitamin, read the label carefully. Look for one that does not contain beta-carotene and consider adding a standalone vitamin C supplement on top of it. The doses of B vitamins in most multivitamins are generally adequate, though the form of B12 matters as discussed above.
E-Cigarettes Are Not Off the Hook
If you have switched from cigarettes to vaping, your vitamin C levels are probably still suffering. A recent study measured blood vitamin C in exclusive e-cigarette users and found their levels nearly identical to those of cigarette smokers: about 37 micromoles per liter for vapers versus 39 for smokers, compared with 55 for nonsmokers. Roughly two-thirds of both vapers and smokers had vitamin C levels considered inadequate, compared with about 43% of nonsmokers.21PubMed Central. Serum Vitamin C Levels in Users of Electronic Cigarettes, Cigarette Smokers and Nonsmokers E-cigarette aerosol contains free radicals and reactive compounds even though it lacks most of the thousands of chemicals in tobacco smoke. The oxidative stress from vaping appears sufficient to deplete vitamin C to a similar degree. Vapers should consider the same vitamin C supplementation strategy as smokers.
Secondhand Smoke and Nutrient Depletion
People regularly exposed to secondhand smoke also take a vitamin C hit. A study comparing passive smokers with both active smokers and unexposed nonsmokers found that passive smokers’ blood vitamin C levels fell between the two groups. About 12% of passive smokers had outright hypovitaminosis C, compared with 24% of active smokers and none of the unexposed group. The vitamin C depletion occurred despite similar dietary vitamin C intakes, meaning it was driven by the smoke exposure itself rather than dietary differences.22The American Journal of Clinical Nutrition. Reduced plasma ascorbic acid concentrations in nonsmokers regularly exposed to environmental tobacco smoke Research has also shown that vitamin C supplementation can reduce a marker of oxidative damage (F2-isoprostanes) in nonsmokers exposed to secondhand smoke.23PubMed. Vitamin C supplementation decreases oxidative stress biomarker f2-isoprostanes in plasma of nonsmokers exposed to environmental tobacco smoke If you live or work with smokers, extra vitamin C is worth considering even though you are not lighting up yourself.
Pregnant Smokers Have a Unique Situation
Smoking during pregnancy creates nutritional demands that affect both mother and baby. A narrative review examining vitamin C supplementation in pregnant smokers found generally positive preventive and protective effects across studies looking at placental function, respiratory development, cardiac health, neurological outcomes, and bone formation in the offspring. However, no study demonstrated that vitamin C could completely compensate for the damage caused by nicotine exposure.24PubMed Central. Vitamin C supplementation in nicotine use during pregnancy: A narrative review Some clinical trials have specifically given supplemental vitamin C (500 mg/day) to pregnant smokers who could not quit, with improvements in newborn lung function measured shortly after birth. Quitting remains the most effective intervention by a wide margin, but for those who cannot, vitamin C supplementation during pregnancy appears to offer meaningful partial protection.
Genetics Can Shift the Equation
Not all smokers metabolize nutrients the same way, and genetic variation can determine how much protection a given vitamin provides. One line of research has focused on genes involved in glutathione production, the body’s master antioxidant system. Variants in the GCLC gene (which codes for an enzyme that builds glutathione) were associated with faster lung function decline in smokers, but only in those with the lowest vitamin C intake. Smokers carrying the risky variants who consumed adequate vitamin C did not show the accelerated decline.25American Journal of Respiratory and Critical Care Medicine. Lung Function Loss, Smoking, Vitamin C Intake, and Polymorphisms of the Glutamate-Cysteine Ligase Genes
Another genetic factor involves the GSTM1 gene, which helps detoxify carcinogens. People who carry a null (deleted) version of this gene are less able to process tobacco carcinogens, and one study found a striking 21-fold increase in lung cancer risk for the heaviest smokers with the null genotype who did not receive vitamin E supplementation. Among those who did receive vitamin E, the same high-smoking null-genotype group saw only a 1.3-fold risk increase.26Cancer Epidemiology, Biomarkers & Prevention. Effect of Vitamin Intervention on the Relationship between GSTM1, Smoking, and Lung Cancer Risk Among Male Smokers These genetic studies are still too preliminary to guide individualized supplement prescriptions for most people, but they illustrate why two smokers with identical habits can have very different health outcomes and different responses to supplementation.
What Happens to Nutrient Levels After You Quit
One encouraging finding is that nutrient levels begin recovering after smoking cessation. Research measuring vitamin C and collagen markers found that both rose significantly after smokers quit, moving back toward the levels seen in never-smokers.1PubMed Central. Effect of smoking, smoking cessation, and nicotine patch on wound dimension, vitamin C, and systemic markers of collagen metabolism The timeline for full recovery varies by nutrient. Vitamin C levels can bounce back within weeks of quitting if intake is adequate, while vitamin D and selenium may take longer because their depletion involves slower metabolic processes. B vitamin levels also tend to normalize relatively quickly once the constant cyanide exposure and oxidative drain of smoking stop. During the transition period when you are quitting or recently quit, continuing supplementation makes sense. The body is healing from years of accumulated oxidative damage, and it needs raw materials to do so.
A Practical Supplement Strategy
Pulling this together into something actionable: smokers should focus on a handful of targeted nutrients rather than shotgunning a megadose multivitamin. The priorities, roughly in order of evidence strength, look like this:
- Vitamin C: 200–500 mg daily, ideally split between food sources and a supplement. This is the nutrient most consistently and severely depleted by smoking.
- Vitamin D: Get tested, and supplement 1,000–2,000 IU daily if your levels are low. Most smokers will benefit.
- B vitamins: A B-complex supplement covering folate, B6, and B12 is reasonable. Choose methylcobalamin or hydroxocobalamin forms of B12 rather than cyanocobalamin.
- Selenium: 55–100 mcg daily if your diet is low in seafood, Brazil nuts, and whole grains.
Avoid beta-carotene supplements entirely. If you take a multivitamin, verify it does not include beta-carotene and understand that the vitamin C dose it contains is probably too low on its own. Eating several servings of fruits and vegetables daily provides a matrix of phytochemicals and fiber that supplements cannot fully replicate, and fruit consumption has been directly linked to lower blood cadmium levels in smokers. Supplements are meant to fill gaps, not replace a good diet. And of course, the most effective intervention for every nutrient deficit discussed here is to stop smoking altogether.