Background: Trans fatty acids are said to be formed by the partial hydrogenation of vegetable oils. Some amounts are produced in digestive organs of ruminants and present in dairy products or meat. In Japan, use of trans fatty acids in the foods is prohibited, thus trans fatty acids must come from foods or microbes in the digestive organs. Methods: Plasma levels of fatty acids including trans forms of healthy old men are measured by gas chromatography and correlations between various foods intakes and plasma levels of trans fatty acids such as palmitoelaidic, elaidic and linoelaidic acids are examined. Results: No correlations between various foods intakes and trans fatty acids were found except between intake of preference drinks such as tea or coffee and plasma levels of palmitoelaidic and linoelaidic acids. Conclusion: Since palmitoelaidic acid is cardioprotective, increase in plasma levels of palmitoelaidic acid may indicate that intakes of tea and coffee may be beneficial for heath by increasing palmitoelaidic acids.
Trans fatty acids, unsaturated fatty acids with at least one double bond in the trans form, are formed during the partial hydrogenation of vegetable oils. This process changes vegetable oils to semisolid fats, which can be used in margarines and commercial cooking. The average consumption of industrially produced trans fatty acids in US is 2% to 3% of total calories consumed [
Higher intakes of industrially-produced trans fatty acids (IP-TFA) [
Naturally present trans fatty acids are found in fats of ruminants such as cattle and goats [
The few studies investigating these naturally derived trans FAs have found no clear association with some CHD risk factors or incident disease, although the results have been inconsistent [
Any investigation of the effects of trans fatty acid in specific populations should begin with the estimation of trans fatty acid intake in that population. However, few data are available on individual intakes estimated using trans fatty acid food composition tables in Asian countries, including Japan, in part because nutrient databases cannot keep up with the rapid rate of re-formulation of food oils which markedly changes IP-TFA levels. Several estimates for Japanese populations have been reported, but their validity is questionable. Accordingly, measuring circulating in vivo fatty acid levels is believed to provide important information of roles of TFA in health and diseases.
We have reported that plasma levels of the major industrially-produced trans fatty acids (IP-TFAs; elaidic and linoelaidic acids) were far higher in American men, and levels of the potentially cardioprotective, primarily ruminant-derived trans fatty acid palmitoelaidic acid (POA) were higher in Japanese. [
In the present studies, we examined relationships between various foods intake and plasma levels of 3 important TRAs such as palmitoelaidic, elaidic, and linoelaidic acids.
In Japan, we recruited 44 male volunteers older than 50 who were friends and family members of the research team for this study. Exclusion criteria included the use of medications to treat diabetes, hyperlipidemia, hypertension and/or cardiovascular disease (CVD). Smokers were also excluded.
We asked 44 healthy men older than 50 and checked their health carefully. We examined their blood samples and recruited them if there were no health problems such as diabetes, hypertension or not serious diseases experienced in the past. They did not smoke in the past. We also excluded people who took drugs for dyslipidemia, hyperglycemia, or hypertension. We collected blood samples early morning. Participants were asked not to eat anything after 21:00 PM the previous evening. Plasma specimens were collected for assays of blood parameters. We obtained an informed consent prior to conducting the protocol which had been approved by the Ethical Committee of Showa Women’s University and Saiseikai Shibuya Satellite Clinic.
Fatty acids levels were measured in plasma obtained from ethylenediamine tetraacetic acid anticoagulated blood samples. Samples were frozen at −80 degrees until analyzed at Omegaquant, LLC (Sioux Falls, SD, USA). After thawing, an aliquot of plasma was combined (1:40 parts) with the methylating mixture (boron trifluoride in methanol [14%], toluene, and methanol [35/30/35 v/v]), shaken at 100˚C for 45 minutes. After cooling, 40 parts of both hexane and distilled water were added. After briefly vortexing, the samples were spun to separate layers, and an aliquot of the hexane layer that contained the fatty acid methyl esters was analyzed by gas chromatography as previously described [
Plasma factors were measured after plasma was separated from blood. Ethylenediamine tetra acetic acid (EDTA) was used as an anticoagulant. Blood glucose levels were measured by a hexokinase UV method. Insulin was measured by the CLEIA (chemiluminescent immunoassay) method. We also measured glycemic indexes after giving glucose and sucrose to participants, so that we did not use HbA1c as a marker of glycemia.
Lipid and lipoprotein concentrations such as total cholesterol, HDL (high density lipoprotein cholesterol), LDL (low density lipoprotein) cholesterol, and TG (triglyceride) were determined using a Polychem Chemistry Analyzer (Polymedco Inc.). FFA (free fatty acid) and the concentrations of ω fatty acids such as arachidonic acid, DHA, and EPA were measured by a gas chromatography.
Remnant lipoproteins (RLPs) were isolated from the serum to an immunoaffinity mixed gel containing anti-apolipoprotein A1 and anti-apolipoprotein B100 monoclonal antibodies (Japan Immunoresearch Laboratories, Takasaki, Japan), and the cholesterol and triglyceride concentrations of the unbound fraction were measured as RLP cholesterol and RLP-triglyceride, respectively.
Participants were given self-administered diet history questionnaires and described answers on each item by recollection of diets they took (7 days dietary recall). We used a brief-type self-administered diet history questionnaire (BDHQ) by using which the Japanese Ministry of Health, Labour and Welfare reports National Nutrition Surveys. From these questionnaires, we calculated the intakes of energy, and varieties of foods such as proteins, carbohydrates, lipids vitamins etc.
Most trans fats in the US diet are produced industrially during the partial
Old men (n = 44) | |
---|---|
Age | 62.4 ± 9.6 |
Height (m) | 1.68 ± 0.07 |
Weight(kg) | 68.8 ± 10.9 |
BMI | 24.3 ± 3.2 |
Mean ± SD.
Plasma levels | |
---|---|
Subjects | old men, n = 44 |
TG: triglyceride (mg/dL) | 126.4 ± 81.3 |
HDL-Chol.: HDL-cholesterol (mg/dL) | 60.9 ± 14.6 |
LDL-Chol.: LDL-cholesterol (mg/dL) | 123.7 ± 30.2 |
T-Chol.: total cholesterol (mg/dL) | 209.9 ± 32.3 |
RLP-Chol.: remnant cholesterol (mg/dL) | 7.6 ± 9.6 |
DHLA: dihydrolipoic Acid (µg/mL) | 36.5 ± 10.3 |
AA: arachidonic acid (μg/mL) | 36.5 ± 10.3 |
EPA: eicosapentanoic acid (μg/mL) | 87.1 ± 46.7 |
DHA: docosahexanoic acid (μg/mL) | 158.6 ± 52.2 |
EPA/AA ratio | 0.42 ± 0.21 |
Blood glucose (mg/dL) | 87.1 ± 46.7 |
Mean ± SD.
Fatty acid (%) | Old men |
---|---|
Myristic | 0.7 ± 0.2 |
Palmitic | 22.0 ± 1.3 |
Palmitoelaidic (trans) | 0.2 ± 0.1 |
Palmitoleic | 1.9 ± 0.6 |
Stearic | 7.0 ± 0.7 |
Elaidic (trans) | 0.1 ± 0.01 |
Oleic | 20.0 ± 2.6 |
Linoelaidic (trans) | 0.2 ± 0.1 |
LA_Linoleic | 26.3 ± 4.0 |
Arachidic | 1.3 ± 0.04 |
GLA_gamma_Linolenic | 0.3 ± 0.1 |
Eicosenoic | 0.2 ± 0.04 |
ALA_alpha_Linolenic | 0.7 ± 0.2 |
Eicosadienoic | 0.2 ± 0.03 |
Behenic | 0.15 ± 0.02 |
DGLA_Dihomo_g_linolenic | 1.0 ± 0.2 |
AA_Arachdonic | 6.0 ± 1.1 |
EPA_eicosapentaenoic | 2.5 ± 1.3 |
Lignoceric | 0.22 ± 0.10 |
Nervonic | 0.33 ± 0.18 |
Docosatetraenoic | 0.12 ± 0.04 |
Docosapentaenoic-n6 | 0.14 ± 0.04 |
DPA_Docosapentaenoic-n3 | 0.68 ± 0.26 |
DHA_Docosahexaenoic | 5.0 ± 1.5 |
Mean ± SD.
hydrogenation of vegetable oils. Smaller amounts are present in dairy products and in meat from cows, sheep, and other ruminants, produced by bacteria in their stomachs. The predominant trans-isomer in ruminants is vaccenic acid (18:1 cis-11), from which conjugated linolenic acid (another trans fatty acid) can be formed.
We found that IP-trans fatty acids were lower in Japan vs the US [
Palmitelaidic | Elaidic | Linoelaidic | |
---|---|---|---|
Energy | 0.319 | −0.135 | 0.181 |
Protein | 0.239 | 0.031 | 0.034 |
Animal protein | 0.233 | 0.135 | 0.034 |
Vegetable protein | 0.193 | −0.081 | 0.152 |
Lipid | 0.187 | 0.120 | 0.034 |
Animal lipid | 0.188 | 0.154 | 0.094 |
Vegetable lipid | 0.167 | 0.027 | −0.066 |
Carbohydrate | 0.188 | −0.197 | 0.138 |
Na | 0.128 | 0.033 | −0.073 |
K | 0.223 | −0.015 | 0.137 |
Ca | 0.099 | 0.263 | −0.021 |
Mg | 0.283 | −0.003 | 0.143 |
Phosphrus | 0.230 | 0.088 | 0.020 |
Iron | 0.193 | −0.120 | 0.112 |
Zing | 0.109 | 0.081 | 0.072 |
Cupper | 0.211 | −0.066 | 0.163 |
Mn | 0.422 | −0.059 | 0.113 |
Retinol | 0.307 | −0.195 | 0.054 |
β carotein | −0.001 | −0.049 | −0.005 |
Vit D | 0.295 | −0.001 | −0.066 |
Tochopherol | 0.167 | −0.049 | −0.004 |
Vit K | 0.098 | 0.014 | 0.083 |
Vit B1 | 0.095 | 0.119 | 0.098 |
Vit B2 | 0.246 | 0.169 | 0.135 |
Niacine | 0.320 | −0.012 | 0.081 |
Vit B6 | 0.239 | −0.036 | 0.129 |
Vit B12 | 0.353 | −0.090 | 0.049 |
Folic acid | 0.333 | −0.120 | 0.080 |
Panthothenic acid | 0.299 | 0.120 | 0.083 |
Vit C | 0.214 | −0.040 | 0.034 |
Saturated fatty acids | 0.209 | 0.144 | 0.112 |
Monovalent fatty acids | 0.156 | 0.126 | −0.004 |
Multivalent fatty acids | 0.179 | 0.024 | −0.062 |
Cholesterol | 0.221 | −0.025 | 0.125 |
Soluble dietary fiber | 0.133 | −0.080 | 0.155 |
Insoluble dietary fiber | 0.125 | −0.047 | 0.076 |
Total dietary fiber | 0.082 | 0.027 | 0.089 |
Salt | 0.128 | 0.033 | −0.073 |
Preference drinks | 0.586** | −0.263 | 0.511* |
Mean ± SD. **p < 0.01, *p < 0.05.
by the naturally occurring 16:1 trans (trans-palmitoelaidic acid) [
As stated above, naturally occurring trans fats are consumed in smaller amounts (about 0.5 percent of total energy intake) in meats and dairy products from cows, sheep, and other ruminants; these trans fats are produced by the action of bacteria in the ruminant stomach [
Since trans fatty acids are not used in foods in Japan, all the trans fatty acids must come from meat or dairy products.
We found that there was no relationship between various foods intakes and plasma levels of trans fatty acids in Japanese old men. Only intakes of preference drinks such as tea and coffee had significant relationship with plasma levels of palmitoelaidic acid and linoelaidic acid.
These results seem to indicate that plasma levels of trans fatty acids are not derived from foods but derived by intestinal microbes.
There are some reports indicating that palmitoelaidic acid is a cardioproective factor [
The present reports may indicate that plasma trans fatty acids may be derived not by foods but by intestinal microbes. Such trans fatty acids are beneficial for health due to increase in a cardioprotective trans fatty acid such as palmitoelaidic acid.
The limitations of the present works were that the number of participants was not large enough. We try to continue the work by examining foods intakes and plasma levels of fatty acids. Also we should examine foods intakes and plasma FA levels of young people and old women in the future.
The results are presented as means ± SD. Spearman’s correlation tests were used to examine statistical significance.
Experiments were designed and performed by all of the authors. AT wrote a manuscript. Statistical analyses were done by FS. All authors read the manuscript and approved the final version. All the authors had responsibilities for the final content. No conflicts of interest for any author.
This work has been approved by the Ethical committees of Showa Women’s University and Saiseikai Shibuya Satellite Clinic and has been carried out in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki) for experiments.
This study was supported by grants by NPO “International Projects on Food and Health”.
Shimizu, F., Ishii, Y., Ogawa, M., Takao, T., Koba, S. and Takada, A. (2018) Effects of Various Foods Intakes on Plasma Levels of Trans Fatty Acids in Japanese Old Men. Food and Nutrition Sciences, 9, 797-805. https://doi.org/10.4236/fns.2018.97059