Use of vitamin and mineral supplements and related variables among university students in Seoul

Jung-Hwa Choi; Youjin Je

doi:10.4163/jnh.2015.48.4.352

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Choi and Je: Use of vitamin and mineral supplements and related variables among university students in Seoul

Research Article

J Nutr Health 2015;48(4):352-363.

Published online: 19 January 2015

DOI: https://doi.org/10.4163/jnh.2015.48.4.352

Use of vitamin and mineral supplements and related variables among university students in Seoul

Jung-Hwa Choi¹, Youjin Je^2,^†

¹Department of Food and Nutrition, Soongeui Womens' College, Seoul 100-751, Korea

²Department of Food and Nutrition, Kyung Hee University, Seoul 130-701, Korea

^†To whom correspondence should be addressed. tel: +82-2-961-0258, e-mail: youjinje@khu.ac.kr

Received 7 May 2015 Revised 28 May 2015 Accepted 23 July 2015

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose:

Despite the popularity of dietary supplements, little data are available on their use by university students. The purpose of this study was to examine the use of vitamin mineral supplements and to identify factors related to supplement use among university students.

Methods:

University students (N = 345) in Seoul were surveyed. Survey questions included descriptive demographics, types of vitamin and mineral supplements used, health related lifestyle factors, mini dietary assessment, and knowledge and behaviors related to supplement use.

Results:

Of university students surveyed, 41% consumed vitamin and mineral supplements. Among the supplement users, multivitamins were the most commonly used dietary supplements (68.6%), followed by vitamin C (31.4%) and calcium (17.1%). In particular, the use of vitamin C and iron supplements was more common in females than males (p < 0.05). For the number of supplements taken daily, 32.1% of supplement users consumed 2 or more supplements; 20% of supplement users had almost no knowledge of the supplements being taken. Based on the results of multivariable logistic regression analysis, supplement use was associated with higher interest in their own health, non-smoker, and supplement use by family (p < 0.05). In addition, supplement use was slightly associated with healthy dietary behavior such as consuming a variety of foods (p = 0.05) and current disease status (p = 0.05).

Conclusion:

University students with relatively healthy lifestyles appear to take vitamin and mineral supplements, but they had little knowledge of the supplements. Given high prevalence of dietary supplement use among university students, nutrition education regarding supplement use is needed.

Keywords: vitamins, minerals, dietary supplements, health behavior, university student

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Table 1.

General characteristics of users and nonusers of vitamin and mineral supplements

Variables	Users¹⁾	Nonusers	Total	p-value²⁾
All, N (%)	141 (40.9)	204 (59.1)	345 (100)
Age (years), mean ± SD	23.4 ± 6.8	22.5 ± 2.0	22.8 ± 4.6	0.075
Gender, N (%)
Male	60 (42.6)	89 (43.6)	149 (43.2)	0.843
Female	81 (57.5)	115 (56.4)	196 (56.8)
School year, N (%)
1st year	21 (14.9)	39 (19.3)	60 (17.5)	0.262
2nd year	50 (35.5)	71 (35.2)	121 (35.3)
3rd year	28 (19.9)	51 (25.3)	79 (23.0)
4th year	39 (27.7)	39 (19.3)	78 (22.7)
Graduate	3 (2.1)	2 (1.0)	5 (1.5)
Major, N (%)
Foods and Nutrition	25 (18.0)	21 (10.5)	46 (13.5)	0.046^∗
Other majors	114 (82.0)	180 (89.5)	294 (86.5)
Place of residence, N (%)
Rural community	3 (2.1)	3 (1.5)	6 (1.7)	0.376
Small/middle city	27 (19.2)	51 (25.0)	78 (22.6)
Large city	111 (78.7)	150 (73.5)	260 (75.7)
Monthly's allowance (won), N (%)
< 150,000	7 (5.0)	13 (6.4)	20 (5.8)	0.450
150,000 to < 300,000	27 (19.2)	52 (25.6)	79 (23.0)
300,000 to < 500,000	79 (56.0)	106 (51.7)	184 (53.5)
≥ 500,000	28 (19.9)	33 (16.3)	61 (17.7)
Monthly's family income (1,000 won), N (%)
< 1,500	1 (0.7)	7 (3.5)	8 (2.4)	0.279
1,500 to < 3,000	32 (23.2)	42 (20.7)	74 (21.7)
3,000 to < 5,000	55 (39.9)	91 (44.8)	146 (42.8)
≥ 5,000	50 (36.2)	63 (31.0)	113 (33.1)
Family occupation, medical/public health field
Yes	28 (19.9)	38 (18.6)	66 (19.1)	0.775
No	113 (80.1)	166 (81.4)	279 (80.9)
Use of supplement by family, N (%)
Yes	98 (69.5)	90 (44.1)	188 (54.5)	0.000^∗∗∗
No	43 (30.5)	114 (55.9)	157 (45.5)

¹⁾ Users were defined as subjects who had ever used vitamin/mineral supplements during the previous year.

²⁾ Two-sample t-test, χ² test or Fisher's exact test were used to assess the difference between users and nonusers.

∗ p < 0.05, ∗∗∗ p < 0.001

Table 2.

Health-related variables of users and nonusers of vitamin and mineral supplements

Variables	Users	Nonusers	Total p	p-value¹
BMI (kg/m², mean ± SD)	20.8 ± 2.6	20.9 ± 2.4 2	20.8 ± 2.4	0.716
BMI category, N (%)
< 18.5	21 (15.1)	33 (16.3)	54 (15.8)	0.816
18.5 to < 23	99 (71.2)	140 (69.0)	239 (69.9)
23 to < 25	11 (7.9)	21 (10.3)	32 (9.4)
≥ 25	8 (5.8)	9 (4.4)	17 (5.0)
Smoking status, N (%)
Smokers	16 (11.4)	48 (23.5)	64 (18.6)	0.004^∗∗
Non-smokers	125 (88.7)	156 (76.5) 2	281 (81.5)	0.004^∗∗
Alcohol drinking, N (%)
Rarely drink	63 (45.0)	90 (44.1) 1	153 (44.5)	0.118
1~2 times/week	70 (50.0)	91 (44.6) 1	161 (46.8)
≥ 3 times/week	7 (5.0)	23 (11.3)	30 (8.7)
Coffee drinking, N (%)
Rarely or < 1 cup/day	75 (53.2)	105 (51.5)	180 (52.2)	0.438
1 cup/day	53 (37.6)	71 (34.8) 1	124 (35.9)
≥ 2 cups/day	13 (9.2)	28 (13.7)	41 (11.9)
Physical activity, N (%)
Rarely exercise	53 (37.6)	93 (45.6) 1	146 (42.3)	0.085
1~2 times/week	47 (33.3)	72 (35.3) 1	119 (34.5)
≥ 3 times/week	41 (29.1)	39 (19.1)	80 (23.2)
Sleeping hours, N (%)
< 6 hours/day	43 (30.5)	58 (28.4) 1	101 (29.3)	0.897
6 to < 8 hours/day	74 (52.5)	112 (54.9)	186 (53.9)
≥ 8 hours/day	24 (17.0)	34 (16.7)	58 (16.8)
Disease status, N (%)
Illness	20 (14.2)	15 (7.4)	35 (10.1)	0.039^∗
No illness	121 (85.8)	189 (92.7)	310 (89.9)	0.039^∗
Self-rated health status, N (%)
Poor	17 (12.1)	23 (11.3)	40 (11.6)	0.343
Average	74 (52.5)	122 (60.1) 1	196 (57.0)
Good	50 (35.5)	58 (28.6) 1	108 (31.4)
Interest in health, N (%)
Little interested	13 (9.2)	30 (14.7)	43 (12.5)	0.000^∗∗∗
Average	39 (27.7)	94 (46.1) 1	133 (38.6)
Interested	89 (63.1)	80 (39.2) 1	169 (49.0)

¹⁾ Two-sample t-test or χ²-test were used to assess the difference between users and nonusers.

∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001

Table 3.

Mini dietary assessment (MDA) scores of users and nonusers of vitamin and mineral supplements (Mean ± SD)

Contents	Dietary Scores¹⁾			p-value²⁾
Contents	Users	Nonusers	Total	p-value²⁾
Do you have milk product more than one serving per day?	1.86 ± 0.71	1.76 ± 0.71	1.80 ± 0.71	0.206
Do you have meat, fish, egg and bean at every meal?	2.00 ± 0.62	1.97 ± 0.63	1.98 ± 0.63	0.670
Do you have vegetable besides Kimchi at every meal?	1.97 ± 0.69	1.91 ± 0.69	1.93 ± 0.69	0.392
Do you have fruit every day?	1.79 ± 0.70	1.68 ± 0.67	1.72 ± 0.68	0.116
Do you try to reduce fried food less than twice a week?	1.66 ± 0.73	1.56 ± 0.64	1.60 ± 0.68	0.176
Do you try to reduce the high fat meat less than twice a week?	1.43 ± 0.64	1.42 ± 0.57	1.42 ± 0.60	0.807
Do you try to reduce salt or soybean sauce in your meal frequently?	1.75 ± 0.71	1.54 ± 0.60	1.63 ± 0.65	0.003^∗∗
Do you have three meals regularly?	1.85 ± 0.76	1.74 ± 0.76	1.78 ± 0.76	0.188
Do you try to reduce snack such as ice cream, cake, cookie and coke less than twice a week?	1.51 ± 0.70	1.44 ± 0.63	1.47 ± 0.66	0.337
Do you have a variety of food?	2.03 ± 0.57	1.83 ± 0.61	1.91 ± 0.60	0.003^∗∗
Total	17.8 ± 4.01	16.8 ± 3.59	17.2 ± 3.81	0.016^∗

¹⁾ Minimum and maximum score for each statement in MDA is 1~3, and that for total statement is 10~30. 1 = seldom, 2 = sometimes, 3 = usually.

²⁾ Two-sample t-test was used to assess the difference between users and nonusers.

∗p < 0.05, ∗∗p < 0.01

Table 4.

Factors related to the use of vitamin and mineral supplements by logistic regression

Characteristics	Crude OR¹⁾ (95% CI²⁾)	Adjusted OR (95% CI)
Major
Other major	1.0 (reference)	1.0 (reference)
Foods and nutrition	1.88 (1.01~3.51)^∗	1.34 (0.67~2.69)
Use of supplement by family
No	1.0 (reference)	1.0 (reference)
Yes	2.89 (1.84~4.54)^∗∗∗	2.74 (1.69~4.43)^∗∗∗
Smoking status
Smokers	1.0 (reference)	1.0 (reference)
Non-smokers	2.40 (1.30~4.44)^∗∗	2.01 (1.04~3.89)^∗
Disease status
No illness	1.0 (reference)	1.0 (reference)
Illness	2.08 (1.03~4.22)^∗	2.15 (0.99~4.74)
Interest in health
Little interested	1.0 (reference)	1.0 (reference)
Average	0.96 (0.45~2.03)	0.81 (0.36~1.81)
Interested	2.57 (1.25~5.26)^∗	1.76 (0.80~3.89)
Trend p-value	0.0001^∗∗∗	0.049^∗
Dietary behavior of reducing salt or soybean sauce
Seldom	1.0 (reference)	1.0 (reference)
Sometimes	1.30 (0.82~2.05)	1.01 (0.61~1.68)
Usually	3.68 (1.67~8.14)^∗∗	2.22 (0.92~5.39)
Trend p-value	0.003^∗∗	0.672
Dietary behavior of having a variety of food
Seldom	1.0 (reference)	1.0 (reference)
Sometimes	2.08 (1.18~3.67)^∗	1.78 (0.95~3.32)
Usually	2.95 (1.39~6.28)^∗∗	1.89 (0.81~4.43)
Trend p-value	0.003^∗∗	0.051

¹⁾ OR: odds ratio 2) CI: confidence interval

∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001

Table 5.

Prevalence of different types of supplements among users

Type of supplements	Number of Supplement Users Taking the Specified Supplement, N (%)
Type of supplements	All¹⁾	Males	Females	p value²⁾
Number of supplement users	140 (100)	59 (42.1)	81 (57.9)
Multivitamin	96 (68.6)	44 (74.6)	52 (64.2)	0.191
Multivitamin/mineral	15 (10.7)	6 (10.2)	9 (11.1)	0.859
Vitamins
Vitamin C	44 (31.4)	13 (22.0)	31 (38.3)	0.041^∗
Vitamin D	8 (5.7)	1 (1.7)	7 (8.6)	0.138
Vitamin B-complex	8 (5.7)	3 (5.1)	5 (6.2)	1.000
Vitamin A	6 (4.3)	3 (5.1)	5 (3.7)	0.697
Vitamin E	4 (2.9)	0	4 (4.9)	0.138
Folic acid	3 (2.1)	0	3 (3.7)	0.263
Vitamin K	2 (1.4)	0	2 (2.5)	0.509
Other vitamins	1 (0.7)	0	1 (1.2)	1.000
Minerals
Calcium	24 (17.1)	9 (15.3)	15 (18.5)	0.613
Iron	13 (9.3)	1 (1.7)	12 (14.8)	0.008^∗∗
Magnesium	4 (2.9)	2 (2.5)	2 (3.4)	1.000
Zinc	1 (0.7)	1 (1.7)	0	0.421
Other minerals	1 (0.7)	1 (1.7)	0	0.421
Total number of type of vitamin and mineral supplements taken daily
1	95 (67.9)	43 (72.9)	54 (58.7)	0.201³⁾
2	23 (16.4)	10 (17.0)	13 (16.1)
3	14 (10.0)	4 (6.8)	10 (12.4)
≥ 4	8 (5.7)	2 (3.4)	6 (7.4)

¹⁾ One supplement user was not included in this analysis since he did not report types of supplements that he used.

²⁾ χ²-test or Fisher's exact test were used to assess the gender difference in each type of supplement use.

³⁾ Calculated using a trend test across the ordered groups.

∗p < 0.05, ∗∗p < 0.01

Table 6.

The knowledge of vitamin and mineral supplements and related behaviors among users N (%)

Variables	Supplement Users			p value²⁾
Variables	All¹⁾	Males	Females	p value²⁾
Nutritional knowledge on the supplements
Seldom know	28 (20.0)	11 (18.6)	17 (21.0)	0.894
Slightly know	87 (62.1)	38 (64.4)	49 (60.5)
Accurately know	25 (17.9)	10 (17.0)	15 (18.5)
Do you usually purchase by yourself?
Yes	48 (34.3)	28 (58.3)	20 (41.7)	0.005^∗∗
No	92 (65.7)	31 (33.7)	61 (66.3)
Do you perceive the recommended daily dosage and take the amount accordingly?
Yes	89 (64.0)	36 (61.0)	53 (66.3)	0.525
No	50 (36.0)	23 (39.0)	27 (33.8)
Consumption of other health functional foods?
Yes	34 (26.2)	15 (27.3)	19 (25.3)	0.804
No	96 (73.9)	40 (72.7)	56 (74.7)

¹⁾ Subjects who had missing values on some variables were not included in the corresponding analyses.

²⁾ χ²-test was used to assess the gender difference in variables.

∗∗p < 0.01

Table 7.

The experience of the effect of vitamin and mineral supplements and opinion of future use among users N (%)

Variables	Supplement Users			p value²⁾
Variables	All¹⁾	Males	Females	p value²⁾
Experience of the effect of supplement use
Improved health	59 (42.1)	23 (39.0)	36 (44.4)	0.518
Not improved health	81 (57.9)	36 (61.0)	45 (55.6)
Experience of any side effects due to the supplements
Have side effects	3 (2.1)	0 (0.0)	3 (3.7)	0.263
No side effects	137 (97.9)	59 (100)	78 (96.3)
Opinion of future use
Continue to use	111 (79.3)	43 (72.9)	68 (84.0)	0.111
Stop using	29 (20.7)	16 (84.0)	13 (16.1)

¹⁾ One subject who had missing values on variables was not included in this analysis.

²⁾ χ²-test or Fisher's exact test were used to assess the gender difference in variables.

Table 8.

Reasons for taking vitamin and mineral supplements and information sources among supplement users N (%)

Variables	Supplement Users			p value¹⁾
Variables	All¹⁾	Males	Females	p value¹⁾
Reasons for taking supplements
Fatigue recovery	58 (41.1)	19 (31.7)	39 (48.2)	0.115
Disease prevention and health promotion	56 (39.7)	27 (45.0)	29 (35.8)
Nutritional deficiency	22 (15.6)	10 (16.7)	12 (14.8)
Disease treatment and others	5 (3.6)	4 (6.7)	1 (1.2)
Information sources for supplements
Family and relatives	85 (60.3)	29 (48.3)	56 (69.1)	0.032∗
Mass media (e.g.,TV, the Internet, magazine)	23 (16.3)	12 (20.0)	11 (13.6)
Friends	20 (14.2)	12 (20.0)	8 (9.9)
Recommendation by health professionals	7 (5.0)	2 (3.4)	5 (6.2)
School class and others	6 (4.2)	5 (8.3)	1 (1.2)

¹⁾ Fisher's exact test was used to assess the gender difference in variables.

∗p < 0.05

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