Dietary Hemp Seeds More Effectively Attenuate Disorders in Genetically Obese Rats than Their Lipid Fraction

Abstract

Background Hemp seeds are rich in PUFAs and other bioactives that can attenuate the development of obesity-related disorders; however, the extent to which their lipid fraction is responsible for this effect is unknown. Objective We hypothesized that hemp seed or hemp oil supplementation can attenuate genetically determined disorders and that the former are more effective in doing so. Methods Lean and obese male Zucker rats, aged 8 wk, weighing 174 ± 4.2 g and 223 ± 3.8 g, respectively, were allocated to 4 groups. The lean (LC) and obese controls (OC) were fed a standard diet, whereas the other 2 obese groups were fed a modified diet in which hemp oil (4% diet; O + HO) or hemp seeds (12% diet; O + HS) were included. All diets had the same proportions of protein (18%), fat (8%), and fiber (5%) and a similar carbohydrate proportion (∼52%). Diets fed to O + HO and O + HS had similar fatty acid profiles. After 4 wk, markers of gut and liver function, antioxidant status, and lipid metabolism were measured. Results The total SCFA concentration in the cecal digesta was lower in OC (64.8 ± 4.21 µmol/g) compared with LC (78.1 ± 2.83 µmol/g) (P ≤ 0.05), whereas it was greater in O + HS (89 ± 4.41 µmol/g) compared with LC, OC, and O + HO (69.7 ± 2.68 µmol/g) (P ≤ 0.05). Plasma total cholesterol was greater in OC (6.20 ± 0.198 mmol/L) and O + HO (5.60 ± 0.084 mmol/L) compared with LC (2.71 ± 0.094 mmol/L) (P ≤ 0.05); in O + HS, the concentration did not differ from the other groups (5.16 ± 0.278 mmol/L). The liver cholesterol concentration was greater in OC (1.79 ± 0.379 mg/g) compared with the other groups (1.28–1.43 mg/g) (P ≤ 0.05). Hepatic expression of peroxisome proliferator-activated receptor γ was lower in OC (11.9 ± 0.93 units) compared with LC (17.3 ± 1.3 units) (P ≤ 0.05), whereas it was greater in O + HS (19.2 ± 1.04 units) compared with OC and O + HO (14.0 ± 1.33 units) (P ≤ 0.05). Conclusions Dietary hemp seeds more effectively attenuate metabolic disorders in genetically obese rats than the oil extracted from them, which suggests that the lipid fraction is only partly responsible for these effects.

Comparative Effects of Dietary Hemp and Poppy Seed Oil on Lipid Metabolism and the Antioxidant Status in Lean and Obese Zucker Rats

“…Another important factor in the modulation of the lipid profile might have been the rat phenotype. In our previous study on obese Zucker rats, a reduction of the plasma HDL cholesterol level after dietary supplementation with hemp seed oil was also observed [35]. Interestingly, changes in the blood lipid profile were not the case in healthy animals, which confirms our hypothesis that the health state of rats is an important factor in the modulation of lipid metabolism by the tested oils.…”

The Effect of Hemp (Cannabis sativa L.) Seeds and Hemp Seed Oil on Vascular Dysfunction in Obese Male Zucker Rats

“…Thus, the decreased plasma uric acid by the seeds in the present study can be considered beneficial for the body, especially when looking at its role in the development of gout. Support of this supposition can be found in the study by Opyd et al [9], who showed that dietary supplementation with hemp seeds improved the antioxidant status of the liver in Zucker rats by increasing glutathione levels and decreasing a marker of lipid peroxidation. This means that a considerable decrease in the plasma antioxidant capacity and uric acid level does not automatically exclude benefits coming from hemp seed supplementation to the organ's antioxidant defense system.…”

“…An interesting and relatively less known source of fatty acids is the seeds of industrial hemp ( Cannabis sativa L.), as they contain a large amount of PUFAs, including linoleic and α-linolenic acids (approx. 53% and 18% of total fatty acids) and some small amount of other fatty acids that are uncommon in vegetable oils, such as γ-linolenic acid [ 8 , 9 ]. The oil from hemp seeds is characterized as having an optimal ratio of n-3 to n-6 PUFAs (1:3), so important for the adequate functioning of the cardiovascular system; however, hemp oil contains trace amounts of trans fatty acids, which are generally thought to raise the risk of atherosclerosis by inhibiting the synthesis of other PUFAs in arterial cells [ 7 , 9 ].…”

“…53% and 18% of total fatty acids) and some small amount of other fatty acids that are uncommon in vegetable oils, such as γ-linolenic acid [ 8 , 9 ]. The oil from hemp seeds is characterized as having an optimal ratio of n-3 to n-6 PUFAs (1:3), so important for the adequate functioning of the cardiovascular system; however, hemp oil contains trace amounts of trans fatty acids, which are generally thought to raise the risk of atherosclerosis by inhibiting the synthesis of other PUFAs in arterial cells [ 7 , 9 ]. Nevertheless, Al-Khalifa et al [ 10 ] demonstrated that hearts from rats fed with hemp seeds exhibited significantly better postischemic recovery of maximal contractile function and relaxation during reperfusion compared to the control group.…”

“…However, hemp seeds are also rich in peptides that have been recognized as a potential antihypertensive agent [ 11 ] and lignan amides with potential anti-inflammatory and cardiovascular activities [ 12 ]. Moreover, in the latest study conducted in one of our laboratories, relatively strong hypolipidemic effects of dietary hemp in genetically obese rats were observed, and the oil fraction was only partially responsible for these effects [ 9 ].…”