The evidence from numerous surveys shows that dietary supplements users are more likely than nonusers to adopt a number of positive health-related habits. These include better dietary patterns, exercising regularly, maintaining a healthy body weight, and avoidance of tobacco products.

Users of dietary supplements are distinct from nonusers in a number of demographic ways. It has been noted, for instance, that supplement use among adults rises in tandem with age, income, and level of education, and that women are more likely to supplement than males across the board.

Although these sociodemographic factors may contribute to the observed differences in health awareness and health habits of supplement users, compared to nonusers, in most studies and for most population groups, the differences in health habits consistently remain significant after adjusting for demographic factors.

Usage is higher in women; and increases with age

Numerous studies support the findings that older age groups use dietary supplements more frequently than younger adults and that women use dietary supplements more frequently than men in each age group. Dietary and health surveys indicate that women may be more health conscious than men; however, the higher rates of supplement use among women may also be partly explained by the increased use of supplemental calcium and vitamin D among women for the purpose of preserving bone health throughout life and preventing the onset of osteoporosis as they age.

In the National Health and Nutrition Examination Surveys (NHANES) conducted from 2003 to 2006, supplement consumption was more common among men and women in different age groups. Males use dietary supplements more frequently than women do, from 36% to 66% of males and 43% to 75% of women, respectively, as people get older. Usage is 7 to 14% (on average, 10%) higher in women than in men in each age group.

Race, ethnicity

The prevalence of dietary supplement use varies by race or ethnicity, with non-Hispanic Whites (hence referred to as Whites) showing the highest prevalence. Dietary supplement use was over 60% among Whites, 36% among Blacks, and about 34% among Hispanics in the NHANES surveys from 1999–2000 and 2003–2006. In the Multiethnic cohort, supplement use was reported by 69% of Whites, 68% of Japanese Americans, 66% of African Americans, 62% of Latinos, and 53% of native Hawaiians. These disparities were not present or were less pronounced in this cohort.

Prevalence of multivitamin use among supplement users

Most dietary supplement consumers take a multivitamin (with or without minerals), regardless of other products. In NHANES 1999–2000, 67% of supplement users used multivitamins. NHANES 2003–2006 found that 74% of supplement consumers took multivitamins. Surveys have used several definitions of “multivitamin” for scientific investigation.

Generally, a “multivitamin” in NHANES surveys contains three or more vitamins, with or without minerals, but this might vary. Commercially, “multivitamin” refers to a product with all or most of the vitamins, while “multivitamin/multimineral” refers to a product with several minerals as well.

According to surveys, those with greater levels of education use supplements more frequently than those with lower levels. In the NHANES 2003–2006 study, just 37% of participants with less than a high school diploma utilized supplements, compared to 61% of those with greater education.

In the NHANES 1999-2000, just 35% of people with less than a high school education reported using supplements, compared to 62% of those with more than a high school degree. The Multiethnic cohort and the VITAL trial both found a favorable correlation between education level and supplement use.

Obese people are less likely to be supplement users

One good habit that supplement users appear to have embraced is making a greater effort to maintain normal body weight or to avoid obesity. In the NHANES 2003–2006 study, supplement consumption was reported by 56% of subjects who were normal weight and 57% of subjects who were overweight, but only 48% of subjects who were obese.

The NHANES 1999-2000 study showed findings that were similar. Obese people were also shown to be less likely to start using supplements in the Multiethnic cohort.

People who exercise are more likely to use supplements

Getting regular exercise is another healthy behavior that tends to be somewhat more prevalent among supplement users than nonusers. In the NHANES 1999–2000 study, supplement consumption was 59% among participants who reported engaging in moderate to intense physical exercise and 43% among those who did not. Regular physical activity was also favorably related to supplement consumption in the Multiethnic group.

Smoking

Users of dietary supplements are frequently nonsmokers or former smokers, which is universally acknowledged as a healthy or desirable lifestyle choice. Supplement users are less likely to be current smokers. In comparison, 43% of current smokers, 61% of former smokers, and 52% of those who had never smoked reported using supplements in the NHANES 1999-2000. Current smokers were similarly discovered to be less likely to indicate supplement use in the Multiethnic cohort.

Beer, wine and spirits

In the first NHANES study (1971–1974), it was shown that wine consumption was linked to a higher prevalence of dietary supplement usage, but beer consumption had no correlation. This was thought to be because supplement users generally had a little higher socioeconomic standing.

In the NHANES 1999–2000 study, supplement use was highest (72%) among those who drank wine more than four times per week, compared to 59% among those who drank wine 1-4 times per week and 47% among those who did not, whereas there was little to no correlation with beer consumption.

Additionally, those who consume distilled spirits more than four times per month (62%) were more likely to use supplements than those who do not consume distilled spirits (51%). Similar to NHANES I, these associations probably have something to do with socioeconomic position. There is no indication of excessive consumption if you consume wine or spirits more than four times a month.

Are people with the disease more likely to use supplements?

The association between supplement consumption and certain medical disorders has been studied in some surveys. 1576 cancer survivors and 4951 people with no history of the disease were discovered through analysis of the 2001 and 2003 California Health Interview Surveys. The authors’ investigation into supplement use revealed that “a cancer diagnosis by itself does not have an independent effect on supplement use.” The majority of cancer survivors, however, also suffer from other chronic illnesses, such as cardiovascular, pulmonary, diabetes, arthritis, etc.

In those with no noncancer chronic problems, the prevalence of using two or more dietary supplements was 52%, in those with one noncancer chronic condition it was 64%, and in those with two or more noncancer chronic conditions it ranged from 71 to 76%.

Over 45,000 people who participated in the Vitamins and Lifestyle (VITAL) survey reported using supplements on average 75% of the time. The respondents ranged in age from 50 to 75. Despite the fact that those with diseases or health issues were not more likely to use supplements than those who did not, the amount of supplements used by those with a sickness or health issue was slightly higher than that of those without it.

The problems that were looked at included major illnesses like cancer and heart disease, as well as ailments like arthritis and asthma and complaints like persistent back pain, recurrent indigestion, allergies, and persistent weariness. About 55% of the VITAL survey participants reported having a health issue, whereas 45% reported none.

The average number of supplements consumed by people with health issues was 1.5, compared to 1.35 for people without such issues. 78% of the respondents did not have any major diseases, while 22% did. The average supplement consumption was 1.6 for those with no major disease and 1.7 for those with some serious disease.

These studies do not imply that those who are ill suddenly start using dietary supplements. It appears more likely that those who already take supplements may choose to add something extra to their regimen in response to a health issue or illness state.