**3. Results**

This study identified the top 10 food categories that provided plant sterols for the Polish population, which were cereals, vegetable fats and oils, vegetables, fruits, coffee, cookies and cakes, chocolate products, potatoes, and legumes. The other food products providing lower amounts of plant sterols were classified into the category of "other food products". Among all of these categories, cereals and fats provided 61% of the total plant sterols, and together with vegetables and fruits, this totaled 80%. Median total plant sterol intake in this study was 255.96 mg/day, and divided by men and women was 291.76 and 230.61 mg/day, respectively (Table 2). Considering individual foods (mg/day), canola oil provided the most plant sterols at 16.92%, followed by white bread at 16.65% and soft margarine at 8.33%. Among vegetables and fruits, there was no single significant source of plant sterols, but raw fruits and vegetables provided the predominant amounts of plant sterols (9.78% and 7.27%, respectively). This pattern of plant sterol sources was reflected in men, while among women, the main contributor was canola oil, followed by white bread, raw fruits, raw vegetables and soft margarine. Gender differences were found for most sources of plant sterol intake.

Figure 3 shows the intake of plant sterols in the Polish population (total, men, women) compared to other populations. With a plant sterol intake of 255.96 mg/day, the data for Poles are within the range for other populations.

Tables 3–5 show the contribution of food categories to the consumption of individual plant sterols such as β-sitosterol, campesterol, and stigmasterol. The median β-sitosterol consumption was 160.85 mg/day, while the intake of campesterol and stigmasterol was 47.45 mg/day and 22.10 mg/day, respectively.

The main food categories providing β-sitosterol were cereals (29.19%), fats (28.86%), fruits (14.20%), and vegetables (8.70%), with a total share of 80.95% of the β-sitosterol supply (Table 3). Among the food products, β-sitosterol was supplied by canola oil (15.88%), followed by wheat bread (14.88%) and soft margarine (9.02%). Women had a lower βsitosterol intake compared to men at 146.28 mg/day vs. 180.84 mg/day, respectively.

The main sources of campesterol were fats (44.95%) and cereal products (31.81%), which together accounted for 76.76% of the campesterol intake (Table 4). For individual products, campesterol was supplied by canola oil (33.43%), white bread (16.30%), and soft margarines (8.11%). Men consumed more campesterol compared to women (56.71 vs. 40.88 mg/day, respectively).

As for stigmasterol, its main sources were the following product groups: coffee (25.10%), vegetables (23.22%), fats (16.85%), and cereal products (12.93%). The foods supplying the highest amounts of stigmasterol included coffee (as a food product; 25.10%), soft margarine (11.82%), and white bread (6.48%). The median intake of stigmasterol was higher in men at 23.49 mg/day compared to women at 21.11 mg/day.





12






 *p* category, only products strongest impact plant 




**Table 4.**

*Cont.*


16






*p* calculated for differences between men and women. \*\* In the total and each food category, only individual food products with the strongest impact on the total plant sterol intakes were

**Figure 3.** Intake of plant sterols in the Polish population and in other countries.

On a per milligram basis, men consumed more total and individual plant sterols (Table 6). However, per 1000 kcal, significantly more plant sterols as total and individual sterols were consumed by women (*p* < 0.0001), except for campesterol, for which the difference was not statistically significant.

**Table 6.** Comparison of total and individual sterol intakes (in mg and in mg/1000 kcal) by men and women.


#### **4. Discussion**

This is the first report on dietary plant sterol intake and its dietary sources in the Polish population. Due to the lack of plant sterols in Polish food composition tables, the database used for this study included international databases available in English supplemented with data from research papers on plant sterol contents in food products. In our study, the consumption of plant sterols from enriched food products was not taken into consideration, since the percentage of consumers of phytosterol-enriched products was low (2%). In comparison, it has been estimated that regular consumers of products with added plant sterols represent approximately 10–15% of the EU population [39].

Typical contemporary Western diets provide much lower amounts of phytosterols [40] than estimated for distant human ancestors, whose diet provided 1 g/day of phytosterols [41]. The dietary phytosterol intake in population studies is usually between 200

and 400 mg/day [21,42], even in those populations with more beneficial dietary habits [43], and this amount is too low to show significant LDL cholesterol-lowering effects demonstrated for 1 g of phytosterols [44]. Contrary to this, the PREDIMED study found that even small amounts of plant sterols from natural foods may exert a cholesterol-lowering effect [45]. A recent meta-analysis of 124 clinical studies demonstrated that a phytosterol intake between 0.6 and 3.3 g/day is associated with a gradual decrease in the concentration of LDL-cholesterol from 6% to 12% [46]. Scientific evidence indicates that even moderate doses of phytosterols delivered via a normal diet can provide a protective effect on the lipid profile by reducing cholesterol absorption [47,48], but a lipid-lowering effect may depend on the inter-individual variation in response to phytosterols [49].

The daily intake of total plant sterols in our study (255.96 mg/day) is similar to that of the Spanish population, where it was estimated to be 276 mg, with the largest contribution of beta-sitosterol (79.7%) [5]. In different populations, plant sterol intake ranged from 230 to 324 mg/day. Among other things, these differences may be due to the dietary habits of different populations or the availability of different food products on the market. Some differences may also be due to the food intake methodology. Some studies were based on a 24-h interview or dietary records, and others on a frequency of intake. Our results confirm earlier findings that β-sitosterol is the most important contributor (67.8%) to the intake of total dietary plant sterols. Regarding gender differences in plant sterol intake, in our study, the intake was 291.76 mg/day for men and 230.61 mg/day for women. These results are similar to most other populations where gender differences in plant sterol intake were observed among men and women [20]. These differences may be due to differences in food intake between the two sexes. Women tend to consume smaller portions of foods, which translates into fewer ingredients including plant sterols.

As per our study, the consumption pattern of total plant sterols from major food groups such as cereal products, vegetable oils and fats, vegetables, and fruits is similar to the intervention group in the PREDIMED study and to the U.K. population [21,45]. Of these, cereal products and oils provided nearly 61% of plant sterols, and when combined with vegetables and fruits, nearly 80%. However, unlike the PREDIMED study, where legumes were the fifth contributor to total plant sterols, in our study, the additional sources of plant sterols included coffee, cookies and cakes, chocolate products, and potatoes, while legumes were only ninth in providing plant sterols. Together, these minor sources of plant sterols accounted for 16.68% of plant sterol intake. The other sources of plant sterols accounted for 3.55%; these included, among others, nuts and seeds, which are normally a good source of plant sterols, but because of their low intake [50], they were not a significant source of plant sterols for the Polish population. The PREDIMED intervention study indicated an important role for the Mediterranean diet, in combination with nuts, in providing plant sterols in the diet and providing a cholesterol-lowering effect [45]. Considering this, Poles should be encouraged to increase their nut consumption and improve their dietary habits, which are far from the recommended for the prevention of cardiovascular diseases [51,52]. Regarding individual dietary sources of total plant sterols, canola oil and white bread predominated, followed by soft margarine. Similar to a Chinese study, canola oil was the main provider of plant sterols among vegetable fats and oils [53].

As in the study of EPIC-Norfolk population [21], women in the WOBASZ survey had a higher plant sterol density than men. Interestingly, when converted per 1000 kcal, the total plant sterol content did not differ from the values obtained in the EPIC-Norfolk study. For men and women in our study, the amount of plant sterols was 141.0 mg and 154.2 mg, respectively, and in the EPIC-Norfolk study, for men it was 137.33 mg and for women it was 152.4 mg/day.

#### *Limitations*

Some plant sterol values in this study may have been underestimated because only three major sterols (sitosterol, campesterol, and stigmasterol) are typically included in the totals, despite the contribution of other sterols. Although the compiled database facilitated

the calculation of plant sterols, there are some shortcomings due to the lack of data for individual plant sterols. This is mainly due to the fact that the literature data do not provide information on the content of plant sterols in certain food products. For some foods, the values of plant sterols (total and individual) were not found, e.g., no studies were found for chard. No data were found for campesterol or stigmasterol in radishes, wines, and mushrooms. For foods such as chives, blueberries, cherries, pears, raspberries, blackcurrants, walnuts, and pumpkin seeds, no value was found for stigmasterol. Therefore, the values obtained for the sum of individual plant sterols could be lower than the total plant sterol content. Moreover, there are no specific data on the composition of plant sterols in enriched margarine, which is related, among other things, to proprietary manufacturing technologies. In addition, since a small percentage of study participants consumed phytosterol-enriched margarine, they were not included in the calculation of dietary plant sterols.

Furthermore, a limitation of the study is the inclusion in the plant sterol database of results from several less rigorous literature sources than those given in the Rand criteria.

This study used single 24-h recall as a tool to measure food intake, which is an appropriate method for large-scale studies. However, 24-h recall does not account for variability in food intake and may not describe a typical diet.

#### **5. Conclusions**

This is the first study to evaluate the intake of plant sterols in the Polish population. Since no plant sterols are listed in Polish food composition tables, a database was developed using published data sources. The study found that plant sterol intake in Poland is 255.96 mg/day, which is comparable to other populations, despite different methodologies of nutritional assessment and slightly different databases. The main dietary sources of plant sterols in this study were cereals, fats, vegetables, and fruits, which is consistent with data for other populations. This study found that women's diets are more dense in plant sterols, which is in agreement with other studies. Due to the lack of literature sources on plant sterol content in some foods, future studies should expand and complete the databases on plant sterol content in foods.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/ 10.3390/nu13082722/s1, Table S1: Content of selected plant sterols (stigmasterol, campesterol, betasitosterol) and total plant sterols in food products (mg/100 g of product), Table S2: Content of selected plant sterols (stigmasterol, campesterol, beta-sitosterol) and total plant sterols in dishes (mg/100 g of dish).

**Author Contributions:** Conceptualization, A.W. and A.M.W.; methodology, A.M.W., A.W. and M.E.Z.; software, A.W., A.M.W. and A.C.-M.; validation, A.W., A.M.W. and I.M.-C.; formal analysis, A.C.-M. and A.W.; investigation, A.W. and A.M.W.; resources, A.M.W., A.W., M.E.Z., I.M.-C. and W.D.; data curation, A.W. and A.M.W.; writing—original draft preparation, A.M.W.; writing—review and editing, A.W., M.E.Z., I.M.-C., A.C.-M. and W.D.; visualization, A.W. and A.M.W.; supervision, A.W., A.M.W. and W.D.; project administration, A.M.W. and A.W.; funding acquisition, A.W. and A.M.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Institute of Cardiology (Grant no. 2.20/I/20) and Medical University of Bialystok (Grant no. SUB/3/DN/21/001/3317).

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Bioethics Committee of the National Institute of Cardiology (protocol code 1344, date of approval 5 November 2012, and protocol code 1837, date of approval 14 January 2020).

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** All data in this study are made available upon request to the authors at the following e-mail address: anna.witkowska@umb.edu.pl or awaskiewicz@ikard.pl.

**Conflicts of Interest:** The authors declare no conflict of interest.
