Hemp Food Product Consumption for 4 Weeks Raises Red Blood Cell Alpha Linolenic Acid, but not Total n‐3 Polyunsaturated Fatty Acid Content, Compared to a Soybean and Sesame Control Product in Free Living Participants who are Overweight or Obese.
Authors: Mackay Dylan S , Cardillo Adrianne , Mollard Rebecca C , Jones Peter J 
Published: November 2023

Hemp foods are an excellent source of omega‐6 (n‐6) polyunsaturated fatty acids (PUFA) and omega‐3 (n‐3) PUFA. Hemp seeds and oil contain high amounts of linoleic acid (LA) and alpha linolenic acid (ALA) in approximately a 3 to 1 ratio. Consumption of ALA from other sources, such as flax, have been shown to increase the total n‐3 PUFA in red blood cells (RBC), which may be beneficial for cardiovascular health. Due to historical restrictions on the growing of hemp, the investigation of its health benefits has been limited. Thus, there is a need for nutritional interventions that investigate the potential health benefits of hemp consumption. The objective of this study was to assess the impact of hemp food products on RBC fatty acid profiles and serum lipids following 4 weeks of consumption.

A free‐living, double‐blind, randomized, 2 period cross‐over feeding study (NCT02400203) was conducted in participants who were overweight or obese. Treatment products were hulled seeds and salad dressing which were given for 28 days. Participants were given hulled hemp seeds, and salad dressing containing 30 g/d of hemp oil (hemp treatment), or hulled sesame seeds, and salad dressing containing 30g/d of soybean oil (control). Participants were instructed by the research team to integrate the products (2 prepackaged sachets of seeds, 1 serving of salad dressing) into their daily meals and to avoid other dietary sources of n‐3 PUFA. RBC fatty acid content was measure by GC‐FID and serum lipids were measured by automated colorimetric assay.

A total of 37 participants were enrolled and 30 participants completed the study protocol. No difference was seen in RBC n‐3 PUFA at the end of the hemp treatment compared to the control (8.07 % ± 0.22 % vs. 7.99 % ± 0.22 %, p=0.72). However, RBC ALA was increased at the end of the hemp treatment compared to control (0.36 % ± 0.02% vs. 0.25 % ± 0.02%, p=0.002). There was no difference in RBC n‐6 PUFA at the end of the hemp treatment compared to the control (32.7 % ± 0.35 % vs. 32.01 % ± 0.35 %, p=0.10), and no difference in RBC n‐6 to n‐3 ratio was seen at the end of the hemp treatment compared to the control (4.12 ± 0.11 vs. 4.10 ± 0.12, p=0.85). There was also no difference between treatments in RBC monounsaturated or saturated fatty acids percentages (p=0.28 and p=0.32, respectively). Total cholesterol was not different at the end of the hemp treatment compared to the control (p=0.53). LDL cholesterol, HDL cholesterol and triglycerides were not different at the end of the hemp treatment compared to the control (p=0.22, p=0.11, and p=0.75, respectively). These results suggest that consumption of hulled hemp seeds and oil does not lead to increased RBC n‐3 PUFA, at least not within 4 weeks. Since ALA competes with LA for elongation, the high n‐6 content of hemp may limit the elongation of ALA to longer chain n‐3 PUFA. Therefore, the fatty acid composition of hemp may not be ideal for someone looking to increase their RBC n‐3 PUFA content.

Support or Funding Information

Governments of Manitoba and Canada through the Growing Forward 2, Growing Innovation – Agri‐Food Research and development Initiative. Matching funds were provided by Manitoba Harvest, Hempro Int. GmbH & Co. KG, and Hemp Oil Canada.