Effects of phylloquinone supplementation on lipid profile in women with rheumatoid arthritis: a double blind placebo controlled study (Kolahi, S, et al.)
Rheumatoid arthritis (RA) is associated with an excess mortality from cardiovascular disease, which is likely attributed to an atherogenic lipid profile. Among nutritional factors, vitamin K has been recently focused as a pivotal nutrient in improvement of lipid-related markers. Thus, this study was designed to determine the effects of vitamin K on lipid profile in this disease.
Fifty-eight patients with definitive RA participated in the present double-blind, placebo-controlled study. They were randomly allocated into two groups to receive vitamin K1 as phylloquinone [10 mg/day] (n = 30) or placebo pills (n = 28), for eight weeks. In order to control the effects of probable confounders dietary intakes, anthropometric measurements including weight and height, clinical status using disease activity score-28 (DAS-28), physical activity and anxiety status were evaluated at baseline. Moreover, serum levels of lipid-related markers including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) were measured at baseline and at the end of intervention.
There were no significant differences between the two groups regarding any of the baseline characteristics. After adjusting for some relevant confounders, in comparison between two groups, the researchers observed no significant changes in lipid-related markers at the end of intervention. Also, there was no significant difference between before and after intervention values within groups (P > 0.05).
“Function of vitamin K1 in lipid profile modification remains still controversial,” the researchers wrote. “This study showed that vitamin K1 has no effect on lipid profile in women with rheumatoid arthritis. Further studies with a longer follow-up are required to determine the effects of vitamin K on atherogenic lipid profile.”
According to Dr. Katarzyna Maresz, president of the International Science and Health Foundation, while the present study showed that phylloquinone (K1) supplementation did not lead to any significant changes in lipids profile in women with rheumatoid arthritis, a few studies investigating the effects of vitamin K on lipid-related markers to date reported conflicting results.
“The study conducted by Kawashima et al. in hypercholesterolemic rabbits showed that Vitamin K2 significantly decreased plasma total cholesterol, lipid peroxidation, and estercholesterol deposition in the aortas of rabbits. Another experimental study in rats indicated a significant reduction in serum triglyceride levels following Vitamin K1- and K2-rich diets (600 mg/kg/day),” said Dr. Maresz. “In this study, the reduction in triglycerides level in phylloquinone group was 48% versus 29% in menaquinone group compared with the control. These data support a presumptive favorable effect of vitamin K1 on lipid profile.”
She added that the researchers noted that the literature on human investigations in this field are sparse. One study, which was conducted in dialysis patients who had osteoporosis due to secondary hyperparathyroidism, found similar results to the previous experimental researches. “This study showed that administration of 45 mg/day of Vitamin K2 as MK-4 reduced serum total cholesterol significantly, without influencing triglyceride and low-density lipoprotein serum levels. In contrast to aforementioned findings, the researchers noted they observed no significant lipid-lowering effect of phylloquinone.
“Based on the available literature, it appears as though Vitamin K2 can, in fact, influence lipid profiles in humans, but Vitamin K1 cannot,” concluded Dr. Maresz. “However, only Vitamin K2 as MK-4 has been tested at this time. We believe more research needs to be done to confirm if milligram doses of MK-4 are a more effective alternative to microgram doses of MK-7.”
Reference: Kolahi S, Gargari BP, Abbasi MM, Jafarabadi MA, Shishavan NG. Effects of phylloquinone supplementation on lipid profile in women with rheumatoid arthritis: a double blind placebo controlled study. Nutr Res Pract. 2015 Apr; 9(2): 186–191.