Effects of Green Wheat ( Triticum turgidum ) and Common Wheat ( Triticum aestivum ) on the Metabolic Profile of Wistar Rats

Abstract

Studies have shown that the consumption of a diet containing whole grains may improve metabolic homeostasis and is related to the reduction of risk factors for the development of obesity, diabetes, cardiovascular diseases, and cancer. We aimed to investigate the effects of Triticum aestivum and Triticum turgidum on the metabolic profile of Wistar rats. Animals were divided into G1 (control group), G2 (T. turgidum), and G3 (T. aestivum). Anthropometric and biochemical parameters were evaluated after 45 days of treatment with both types of wheat. Our results showed that the use of the common or green wheat improved body weight percentage, visceral fat, glycemia, low-density lipoprotein cholesterol, triglycerides, and atherogenic indices such as atherogenic index, CCR1, and CCR2. Furthermore, wheat may also improve high-density lipoprotein cholesterol levels. The health-promoting properties of wheat occur probably due to the content of phytochemicals, antioxidants, and fibers. We suggest that the intake of T. aestivum and T. turgidum may be helpful in the prevention or treatment of obesity, diabetes and cardiovascular diseases.

Introduction

The lifestyle modifications undergone by modern societies led to a reduction in energy expenditure, in addition to an augment in the consumption of foods rich in fats and sugars. This behavior is related to the development of numerous metabolic changes related to the increase in the occurrence of chronic degenerative diseases such as obesity, type 2 diabetes, cardiovascular diseases (CVD), and cancer.^1,2

Numerous studies with plants have arisen in the attempt to find therapeutic alternatives that aid in the prevention or treatment of these diseases.³ Green wheat, also known as freekeh, is the roasted grain. The processing allows the obtaining of grain with flavor and nutritional properties different from the conventional wheat (also called bread wheat).^4,5

The wheat is harvested while the grains are still green and the seeds are still soft. After that, they are piled and sun-dried. Under this process, the moisture content of the seed prevents burning. These grains are rich in dietary fiber and contain a low glycemic index, besides being rich in lutein and zeaxanthin (carotenoids), prebiotics, probiotics, calcium, iron, zinc, and phosphorus.^4,6

Studies have shown that the consumption of a diet containing whole grain wheat may improve metabolic homeostasis. It is also related to the reduction of risk factors for the above-mentioned diseases, perchance due to the presence of high amounts of phytochemicals that are known to act as antioxidants and are able to reduce oxidative stress that is associated with the chronic degenerative diseases.^7

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Based on the wheat properties, we aimed to investigate the effects of the common wheat (Triticum aestivum) and the green durum wheat (Triticum turgidum) on the metabolic profile of Wistar rats.

Materials and Methods

Animal groups

After the approval of the ethics committee (University of Marilia, UNIMAR, SP, Marília) under protocol number 09/2018, we separated 24 male Wistar rats of weight ∼180–220 g (±8.73 g) (animals were divided randomly after body weight was evaluated). These animals were obtained from the Center for Experimentation in Animal Models of the University of Marília, UNIMAR, and were cared for according to the recommendations of the Canadian Council's “Guide for the care and use of experimental animals.”

Before beginning the experimental protocol, the animals underwent an adaptation period of 7 days (12-h light/dark cycle environment, temperature 22°C ± 2°C, and relative humidity of 60% ± 5%) until the end of the experimental protocol. The animals were divided into three groups (n = 8):

G1: control group, animals received water and food ad libitum.

G2: group treated with green durum wheat (T. turgidum), animals received water and rat food supplemented with green durum wheat ad libitum for 45 days.

G3: group treated with whole grain wheat (T. aestivum), animals received water and rat food supplemented with wheat ad libitum for 45 days.

Commercial feed (proper for the species) supplemented with T. aestivum and T. turgidum (20:80) was prepared by crushing the commercial feed and the wheat in an electric mill (4500 rpm). After mixing these components with water (until a homogeneous mixture was obtained), the mixture was handled to produce the final shape similar to the commercial rat food. After this process, an air circulation oven was used at 65°C for 6 h for drying.

We evaluated the body weight of the animals (three times/week), and at the end of the experimental protocol, the animals were anesthetized with thiopental overdose (200 mg/kg) to investigate the anthropometric and biochemical parameters. Immediately after death, blood samples were collected from the vena cava to delineate the evaluation of glycemia, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and triglycerides (TGs). Anthropometric data (body weight, Lee index, thoracic circumference, abdominal circumference, and visceral fat weight) were also evaluated.

Atherogenic coefficient (AtC), atherogenic index (AI), cardiac risk ratios 1 and 2 (CRR1/2), and non-HDL-c were analyzed according to AtC = (TC – HDL-c)/HDL-c; AI = log (TG/HDL-c); CCR1 = TC/HDL-c, CCR2 = LDL-c/HDL-c; non-HDL-c = TC–HDL-c.^11,12

Statistical analysis

Anthropometric and biochemical parameters are expressed as mean ± standard deviation, and ANOVAs were used to analyze the data after going through the normality test (Kolmogorof–Smirnoff). The level of significance was 5%.

Results

In Table 1 it is possible to see that the groups treated with wheat showed a significant reduction in the body weight percentage. G2 also showed significant reduction of visceral fat. However, in group G2, the reduction of body weight and visceral fat was higher.

Table 1.

Anthropometric Parameters of G1 (Control Group), G2 (Group Treated with Triticum turgidum), and G3 (Group Treated with Triticum aestivum)

Parameters	G1	G2	G3	P
% Body weight	117.14 ± 28.86 (A)	53.44 ± 33.21 (B)	35.67 ± 35.67 (B)	.000^*
Lee index	29.37 ± 0.60 (A)	29.31 ± 0.42 (A)	28.76 ± 0.78 (A)	.170
Body mass index	0.57 ± 0.04 (A)	0.56 ± 0.06 (A)	0.53 ± 0.03 (A)	.100
TA	9.10 ± 0.66 (A)	9.20 ± 0.35 (A)	11.70 ± 1.35 (B)	.000^*
AtC	10.8 ± 0.71 (A)	10.45 ± 0.50 (A)	13.25 ± 1.78 (B)	.001^*
Visceral fat	2.11 ± 0.95 (C)	1.46 ± 0.43 (B)	2.67 ± 0.77 (A)	.000^*

Means followed by at least one same letter do not statistically differ.

Significant difference.

AC, abdominal circumference; TA, thoracic circumference.

Table 2 shows a significant reduction in glycemia and LDL-c levels in G3, significant reduction in TGs in G2, and significant increase in HDL-c levels in G3.

Table 2.

Biochemical Parameters of G1 (Control Group), G2 (Group Treated with Triticum turgidum), and G3 (Group Treated with Triticum aestivum)

Parameters (mg/dL)	G1	G2	G3	P
Glycemia	200.1 ± 51.87 (A)	198.00 ± 36.00 (A)	165.8 ± 28.48 (B)	.050^*
TG	120.8 ± 33.32 (A)	89.9 ± 20.70 (B)	106.4 ± 9.18 (A)	.020^*
Cholesterol	163.00 ± 9.17 (A)	158.22 ± 7.28 (A)	159.5 ± 7.25 (A)	.230
HDL-c	41.00 ± 6.16 (A)	39.5 ± 3.02 (A)	46.6 ± 6.38 (B)	.010^*
LDL-c	101.94 ± 7.17 (A)	100.53 ± 8.13 (A)	91.62 ± 6.84 (B)	.011^*

Means followed by at least one same letter do not statistically differ.

Significant difference.

HDL-c, high-density lipoprotein cholesterol; LDL-c, low-density lipoprotein cholesterol; TGs, triglycerides.

In Table 3 it is possible to see that the group treated with wheat presents significant reduction in the AI, and values of CCR1 and CCR2 reduced in G3.

Table 3.

Atherogenic Indices of G1 (Control Group), G2 (Group Treated with Triticum turgidum), and G3 (Group Treated with Triticum aestivum)

Parameters	G1	G2	G3	P ^*
Non-HDL-c	121.00 ± 78.69 (A)	118.44 ± 78.59 (A)	112.90 ± 60.44 (A)	.070
AtC	1.94 ± 1.07 (A)	1.28 ± 0.57 (A)	1.32 ± 0.38 (A)	.080
AI	1.95 ± 1.08 (A)	1.28 ± 0.55 (B)	1.33 ± 0.4 (B)	.030^*
CCR1	4.02 ± 2.43 (A)	3.99 ± 0.31 (A)	3.47 ± 0.47 (B)	.020^*
CCR2	2.43 ± 0.47 (A)	2.54 ± 0.31 (A)	2.01 ± 0.40 (B)	.010^*

Means followed by at least one same letter do not statistically differ.

Significant difference.

AtC, atherogenic coefficient; AI, atherogenic index; CRR1, cardiac risk ratio 1; CRR2, cardiac risk ratio 2.

Discussion

Our results showed that the use of common or green wheat improved anthropometric and biochemical parameters, and atherogenic indices such as AI, CCR1, and CCR2.

Several studies have shown that bioactive compounds isolated from cereals and another vegetable could produce some metabolic effects in human beings. The literature lays emphasis on the health-promoting properties of cereals by including them in the base of the nutritional food pyramid. Researchers have been observing the correlation between the prevention or occurrence of CVD and the adherence to dietary patterns, such as the Mediterranean diet, that is rich in whole grains, legumes, and derived products. Endosperms possess more carbohydrates and proteins and the bark possesses fibers and phytochemicals.^13
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A whole grain consists of bran, germ, and endosperm and its potential to reduce the risk of metabolic disorders is also due to the fiber content. This component is mainly concentrated in the bran fraction and is related to the beneficial effects of whole grains on glucose homeostasis. Some authors found that fiber content present in whole grain, but not in refined grain products, is inversely linked to all-cause mortality, suggesting that fibers and phytochemicals present in bran result in additional benefits other than the effects of fiber alone.^16

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Important phytochemicals present in wheat are the alkylresorcinols.²⁰ These phenolic compounds are mainly located in the bark of the wheat and are readily absorbed in humans²¹ and rats.²² Oishi et al.²³ showed that chronic supplementation with wheat alkylresorcinols prevents insulin resistance, glucose intolerance, and hepatic steatosis resulted from a high-fat high-sucrose diet.

T. aestivum presents a nonspecific lipid transfer protein type 2 (nsLTP2) that is a peptide chemically thermo and protease resistant and exhibits relevant activity in the protection of vascular system against different stressors. This peptide has been identified as exerting antioxidant activity, has potential cytoprotective effects, and downregulates the expression of cell adhesion molecules induced by proinflammatory cytokines.^13,24 Together with the other antioxidants present in wheat, nsLTP2 may be related to the beneficial effects of green and common wheat observed in our results.

Cicero et al.¹³ performed a double-blind randomized feeding-controlled cross-over clinical trial, and the selected patients (prehypertensive healthy subjects) received wheat products containing different amounts of nsLTP2 (bread, pasta, and crisp toasts) naturally with a low or a high amount of nsLTP2, changing the usually consumed foodstuff by the product provided for the study. The product consists of ancient wheat (T. turgidum) and a mixture of organic modern commercial Triticum durum and varieties of T. aestivum that were used in the nsLTP2 low-dose group. The product with the ancient wheat has a high content of nsLTP2 compared with the modern wheat. The use of the ancient wheat showed a reduction in glycemia, TG levels, blood pressure, and endothelial reactivity. We found similar results in glycemia and TG levels.

Kumar and Lyer²⁵ investigated the effect of T. aestivum on inflammation, atherogenic lipoproteins, and menopausal symptoms in hyperlipidemic women who received freeze-dried wheat powder in capsules for 10 weeks. They observed that the consumption of these capsules reduced 5.4% of TC, 4.4% of LDL-c, and 9.5% of TGs. In a randomized double-blind placebo-controlled crossover trial, Saito et al. ⁸ showed improvement in glycemia in individuals treated with wheat albumin and found that this treatment is a useful food component for glycemic control during the night.

In diabetic Wistar rats, Mohan et al.²⁶ evaluated the antidiabetic and antioxidant effects of ethanolic extracts of T. aestivum and observed a significant reduction in body weight, glycemia, TGs, LDL-c, and very low density lipoprotein-cholesterol. The levels of HDL-c were significantly higher than those found in the control group. Furthermore, these authors showed a decrease in the levels of lipid peroxides, glutathione peroxidase, and superoxide dismutase, showing that this plant exhibits antihyperglycemic, hypolipidemic, and antioxidant activities in diabetic animals.

Suhr et al.²⁷ studied the effects of consumption of whole grain rye compared with consumption of refined rye on the body weight and composition and found that these parameters reduced more in the group that used whole grain wheat. Although these cultivated plants are from different species, they are closely genetically related, allowing the comparison of the results.

The atherogenic indices are also strongly associated with the development and progression of CVD.^12,28 Our results showed that the consumption of common and green wheat might help improving AI, CCR1, and CCR2 and could be used as adjuvants in the prevention of risk factor cardiovascular events. We did not find studies evaluating atherogenic indices after the consumption of wheat.

Most studies in the literature are performed with the common wheat and we studied the green wheat. As far as we know, this is the first time a comparison has been made between the biochemical and anthropometric effects of T. aestivum and T. turgidum. Our results show that wheat consumption (T. aestivum and T. turgidum) can bring benefits to the metabolic profile of animals. However, further studies should be conducted to evaluate whether these results are similar in humans.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

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