International Journal of Nutrition, Pharmacology, Neurological Diseases

ORIGINAL ARTICLE
Year
: 2013  |  Volume : 3  |  Issue : 4  |  Page : 352--357

Amelioration of selected cardiac risk factors through supplementation of diet with flaxseed and soya bean


Charu Katare1, Sonali Saxena2,  
1 Department of Food and Nutrition, Government Kamla Raja Girls (PG) Autonomous College, Gwalior, Madhya Pradesh, India
2 School of Studies in Biochemistry, Jiwaji University, Gwalior, Madhya Pradesh, India

Correspondence Address:
Charu Katare
Department of Food and Nutrition, Government Kamla Raja Girls (PG) Autonomous College, Gwalior - 474 011, Madhya Pradesh
India

Abstract

Aims: Flax seeds and soya bean are a rich source of unsaturated fatty acids, antioxidants and fibers known to have anti-atherogenic activities. The study attempted to evaluate the effect of flaxseed and soya bean supplementation on serum lipids of dyslipidemic subjects. Methods: The subjects were divided into three groups: Experimental group-I (E-I), experimental group-II (E-II) and a control group (C). Group E-I was given 30 g of roasted flaxseed chutney powder and group E-II was given 30 g of soya nuts for 12 weeks. Both groups and the control group were prescribed with similar dietary guidelines. Anthropometric parameters, blood pressure and blood lipid profile were estimated before and after completion of the study. Results: Twelve week therapeutic intervention indicated significant drop (P < 0.05) in blood pressure, whereas a highly significant reduction (P < 0.01) was noted in Total cholesterol and triglycerides. A significant improvement in high density lipoprotein cholesterol was recorded in the groups receiving flaxseed (P < 0.01) and soya bean (P < 0.05). Body mass index, cardiac risk ratio, atherogenic coefficient and atherogenicity index of plasma were also found to improve significantly. Conclusion: These findings suggest that therapeutic intervention with flaxseed and soya may be a preliminary, but efficacious means of improving cholesterol and triglyceride levels in those diagnosed with dyslipidemia and may also be advocated in place of drug therapy when cholesterol levels soar just above the normal range.



How to cite this article:
Katare C, Saxena S. Amelioration of selected cardiac risk factors through supplementation of diet with flaxseed and soya bean.Int J Nutr Pharmacol Neurol Dis 2013;3:352-357


How to cite this URL:
Katare C, Saxena S. Amelioration of selected cardiac risk factors through supplementation of diet with flaxseed and soya bean. Int J Nutr Pharmacol Neurol Dis [serial online] 2013 [cited 2019 Nov 12 ];3:352-357
Available from: http://www.ijnpnd.com/text.asp?2013/3/4/352/119844


Full Text

 Background



Coronary heart disease (CHD) is a leading cause of morbidity and mortality in developed countries and is emerging as an epidemic in developing countries. [1] A majority of young people are unconcerned about their risk for development of this disease. Population based studies in the youth show that the precursors of heart disease start in adolescence. The marked increase in cardiovascular diseases (CVDs) in economically developing countries has resulted from the economic growth and associated socio-demographic changes that have occurred over recent decades. During this period, the burden of illness from infectious disease has fallen and parallel changes. Parallel changes in life-style and diet have led to an increase in life expectancy and a greatly increased burden of CVD and other chronic diseases. Dyslipidemia, a major systemic disorder, is one of the most important risk factors for CVD, which are a major cause of morbidity and a leading contributor to mortality world-wide. [2] Dyslipidemia is one of the modifiable risk factors of CHD, characterized by high triglycerides (TG), decreased high density lipoprotein cholesterol (HDL-C) and increased lipoprotein (LPa). LPa provides a carrier system for low density lipoprotein cholesterol (LDL-C) facilitating cholesterol accumulation in cells. Oxidized LDL-C and LPa accumulate in an excessive amount in macrophages forming fatty streaks, which then leads to the formation of atherosclerotic plaque. [3] Several studies have been conducted on the effect of diet on lipid profile and inflammatory markers, especially on the effect of soy intake; however, most of these studies have been performed on healthy people or hypercholesterolemic or diabetic patients. [4]

Soy is a plant-derived estrogen, known for anti- inflammatory and anti-hyperlipidemic properties which can potentially protect against CVD. [5] Flaxseed is a complex food containing high amounts of polyunsaturated fatty acid (PUFA), mainly alpha-linolenic acid (ALA), which is an (n-3) fatty acid as well as soluble fiber, lignan precursors, and other substances that may have health benefits. [6] Several studies have documented that consumption of PUFA tend to improve blood lipid profile. Hence, the present study aims to investigate the effect of supplementation of diet with flaxseed and soya bean on dyslipidemic subjects.

 Methods



In the present study, 75 dyslipidemic subjects, in the age group of 40-60 years were selected from various areas of greater Gwalior by stratified random sampling (purposive) method [Table 1]. Dyslipidemic subjects with elevated levels (based on Adult Treatment Panel III criteria) [7] of TG (>150 mg/dl) or cholesterol (>200 mg/dl) or low density lipoproteins (>130 mg/dl), who were regular visitors of hospitals and clinics were selected. The subjects were divided into three groups each comprising of 25 subjects.{Table 1}

One group served as the control (C) and remaining two groups as experimental group-I (E-I) and experimental group-II (E-II). The study design and experimental protocols were approved by the Institutional Human Ethics Committee.

The methodology consisted of administration of a pre-tested questionnaire to the subjects to collect general information viz., nutritional status data (height, weight, body mass index [BMI], blood pressure, health complaints, socio-economic status, dietary pattern, medical history and life-style.

At the beginning of the study baseline values for blood pressure, body weight and BMI were recorded. Blood samples were collected from the selected subjects after 12 h from the last meal consumed. Plasma TG was estimated by glycerol-3-phosphate oxidation-peroxidase method, [8] total cholesterol was estimated by cholesterol-oxidase and p-aminophenazone method [9] and HDL-C level was estimated by phosphotungstate method. [10] The LDL and VLDL level was calculated by Friedewald's equation. [11]

The following atherogenic indices [12],[13],[14],[15] were calculated: Cardiac risk ratio (CRR) = TC/HDL-C, atherogenicity coefficient (AC) = (TC − HDL-C)/HDL-C and athrogenic index of plasma [AIP = Log (TG/HDL)].

Several food products were formulated by using flaxseed and soya bean and subjected to sensory evaluation prior to administration. Sensory evaluation was performed by 9 point hedonic scale. [16] The most acceptable preparations were "roasted flaxseed chutney powder (RFCP)" and "soya nuts (SN)."Ingredients and nutritive value [17] of RFCP are given in [Table 2] and [Table 3].{Table 2}{Table 3}

RFCP (30 g) and SN (30 g) were administered to group E-I and group E-II respectively for 12 weeks. The control group was not provided with any supplementation. All subjects were asked to follow similar dietary guidelines. After completion of 12 weeks, estimation of blood lipid profile, measurement of blood pressure and determination of body weight and BMI was done.

 Results



Effect of RFCP and SN administration on body weight and BMI

Control group exhibited mean drop of 0.55% in body weight. Mean Reduction of 2.89% and 1.75% of body weight was noticed in group E-I and group E-II respectively. A significant difference (P < 0.01) in the baseline and final values of body weight and BMI of the subjects receiving RFCP (group E-I) was observed. Group E-II was found to have a significant decrease (P < 0.05) in body weight and reduction in BMI was also highly significant (P < 0.01) [Table 4].{Table 4}

Effect of RFCP and SN administration on blood pressure

A mean drop of 0.35% was recorded in systolic blood pressure in the control group whereas group E-I and E-II showed a mean fall of 0.88% (P < 0.05) and 1.35% (P < 0.05) respectively. The diastolic blood pressure of the control group showed a mean decline of 0.88% and the group E-I and group E-II showed mean fall of 1.91% (P < 0.05) and 1.54% (P < 0.05) in diastolic blood pressure respectively [Table 5].{Table 5}

Effect of RFCP and SN administration on blood lipid profile

Control group exhibited mean lowering of 1.81% in total serum cholesterol level followed by 16.19% (P < 0.01) and 3.79% (P < 0.01) drop in group E-I and E-II. A highly significant reduction (P < 0.01) in TG was noted in groups E-I and E-II with a mean lowering of 13.99% and 11.73% respectively where as a decline of 1.84% was seen in the control group. Elevation of 4.94% (P < 0.01) and 3.21% (P < 0.05) in HDL level was seen in groups E-I and E-II with a considerable change shown by the control group. LDL-C values were also significantly lowered (P < 0.01) in group E-I and group E-II with a mean change of 19.93% and 3.92%. Both experimental groups showed a significant lowering (P < 0.05) of VLDL-C with a mean change of 17.94% and 10.37%, whereas mean drop of 5.35% was seen in the control group [Table 6].{Table 6}

Effect of RFCP and SN administration on cardiac risk

A remarkable improvement in atherogenicity indices was noticed. CRR, AC and AIP were found to be significantly reduced (P < 0.01) in group E-I and group E-II [Table 7].{Table 7}

 Discussion



Twelve week supplementation of RFCP and SN to dyslipidemic subjects indicated that both interventions were well-tolerated by subjects and the dropout rate was minimum. In the present study supplementation of Soy and flaxseed to dyslipidemic subjects resulted in a significant decrease in body weight, BMI, systolic and diastolic blood pressure. A study reveals that daily consumption of flaxseed during a 4-month period may lead to a modest amount of weight loss of up to 0.9 kg. [18] Results of yet another study reported a reduction in abdominal fat among women supplemented with 20 grams of isolated soy protein. [19] Feeding soy protein is also associated with lowering of body weight and fat in rats and mice. [20] A pre-clinical study has shown that soy protein suppresses appetite partly by stimulating the release of cholecystokinin, which regulates satiety and gastric emptying. [21] Soy iso-flavones have been observed to lower blood pressure in hypertensive subjects. [22] The above studies were found to be in agreement with the conclusions of our study on SN and RFCP supplementation. Viscous flaxseed dietary fibers may be a useful tool for lowering blood cholesterol and may also play a potential role in the energy balance. [23]

Supplementation of RFCP and SN to the diet of dyslipidemic subjects brought significant fall in blood pressure, which may be attributed to the presence of PUFA, mainly ALA, soluble fiber, lignan precursors and estrogen in flaxseeds and soya bean. Findings of several studies corroborate with the results of our study. A decrease in diastolic blood pressure was noted in men taking flaxseed lignin when evaluated against the men taking placebo and increased triacylglycerol in men taking placebo compared with men taking flax lignin was observed in a randomized double-blind placebo controlled study. [24] Results of yet another study revealed that Omega-3 PUFA deficiency, particularly during the prenatal period, can cause hypertension in later life. [25] A study attempted to clarify the antihypertensive effect showed that ALA reduced the systolic blood pressure of spontaneously hypertensive rats and its mechanism may be related to increases of prostaglandin I (2) and nitric oxide through bradykinin stimulation. [26]

Administration of SN and RFCP exhibited anti-hyperlipidemic effect conclusive of the highly significant reductions in Total Cholesterol, TG, LDL and VLDL with elevated HDL levels, which also signify cardio protective activity. However, magnitude of the change in lipid profile was greater with RFCP. Results of a study, similar to our findings report that flaxseed consumption by postmenopausal women was found to be effective in reducing total cholesterol, non-HDL-C and apo B levels that are well-known risk factors of CHD. [27] Consumption of Flax drink and Flax bread resulted in decreased total plasma and LDL-C and increased fat excretion, but the food matrix and/or processing may influence these results. [28] In a study highly significant improvement was seen in serum lipid profile and Apolipoprotein A1 and B levels in women taking soy proteins, whereas women taking soy isoflavones demonstrated significant improvement in serum TG. [29]

Major constituents of soy protein and flaxseed, which may be responsible for their lipid lowering effects are claimed to be phytoestrogens, namely isoflavones and lignans. [27] Soy protein isolate is a rich source of isoflavones, genistein and daidzein, [30],[31] which exert hypocholesterolemic effects in animals and humans. [32],[33],[34] The predominant fatty acid in soybean is linoleic acid, although a lesser amount of n-3 fatty acid, ALA, is also found. Linoleic acid has been reported to lower cholesterol. The ratio of linoleic to ALA in soybeans is about 7.5:1. [35] Whole flaxseed contains approximately 41% fat and 21% protein of the seed weight. [36] Unlike soybean, flaxseed is particularly rich in ALA (approximately 57% of the total fatty acids in flaxseed), which has lipid lowering properties. [37] Thus, the reduction of blood cholesterol by either dietary soy protein or flaxseed in these studies may be due in part to linoleic acid and ALA present in whole bean or seed.

Atherogenic index (AI) indicates the deposition of foam cells or plaque or fatty infiltration or lipids in heart, coronaries, aorta, liver and kidney. The higher the AI, the higher is the risk of above organs for oxidative damage. [38] In our study noteworthy improvement in atherogenic indices were observed. In support to our results, another study demonstrated a significant decrease in the degree of lipid peroxidation in the liver when compared with rats fed the same amount of pork lard during 4 weeks of experimental feeding with flaxseed oil enriched diet (16%). Moreover, the addition of soybean oil or flaxseed oil to the diet (16%) significantly decreased triglyceride and total cholesterol blood levels and also reduced AI of plasma. [39]

Dyslipidemia is a state that accelerates the beginning and development of atherosclerosis. Dyslipidemia can often be prevented or treated with life-style management and proper nutrition. Findings of our study indicated beneficial effects of flaxseed and soya bean supplementation on atherogenic lipid profile. And therefore, it can be said that nutritional supplementation can prove very effective and convenient aid in mitigative effect on dyslipidemia.

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