Dietary vitamin B6 supplementation attenuates hypertension in spontaneously hypertensive rats

Appearance of choline metabolites in plasma and milk when choline is infused into the abomasum with or without methionine

Four lactating, ruminally cannulated Jersey cows, (mean ± standard deviation) 264 ± 54.2 d in milk and 484 ± 24.1 kg of body weight, were arranged in a 4 × 4 Latin square design to measure the effects of abomasal infusion of choline chloride with or without dl-Met on milk and plasma choline metabolites and plasma AA in cows fed a Met-deficient diet. Cows were randomly assigned to 1 of 4 experimental treatments: (1) control; no supplemental Met or choline (CON), (2) 13 g/d of choline ion delivered via abomasal infusion (CHO), (3) 13 g/d of Met delivered via abomasal infusion (MET), and (4) 13 g/d of choline and 13 g/d of Met delivered via abomasal infusion (CHO + MET). Cows received the same basal diet throughout the experiment, which was formulated to be deficient in Met (-5.0 g of Met using the NASEM, 2021, model). Periods were 7 d in length with d 1 to 2 serving as a wash-out period and cows being infused on d 3 to 7. Milk samples were collected twice daily on d 5 to 7 and were analyzed for fat, true protein, lactose, and choline metabolites including betaine, phosphocholine, and free choline using hydrophilic interaction liquid chromatography-tandem mass spectrometry. Blood samples were collected via venipuncture of the coccygeal vein at 1100, 1300, and 1500 h on d 7 of each period and were analyzed for free AA as well as choline metabolites. Plasma Met increased in response to Met infusion and an interaction with choline and Met infusion was observed in the plasma concentration of branched-chain AA. Cows receiving choline exhibited the greatest Cho yield in milk. Milk phosphocholine yield tended to be highest when both choline and Met were infused.

The Effect of Pyridoxine Hydrochloride Supplementation on Leptin, Adiponectin, Glycemic Indices, and Anthropometric Indices in Obese and Overweight Women

Obesity has reached epidemic proportions globally. Among several methods for treating obesity, the use of dietary supplements is common recently. One supplement that can help in this regard might be vitamin B6 in high doses. The objective of this study was to evaluate the effect of pyridoxine hydrochloride supplementation on anthropometric indices, body composition, visceral adiposity index (VAI), and metabolic status in obese and overweight women. In this randomized controlled clinical trial, 44 obese and overweight women aged 18-50 years were selected and divided randomly into 2 groups: an intervention group (receiving 80 mg pyridoxine hydrochloride supplement for 8 weeks) and a control group (receiving placebo for 8 weeks). In the pyridoxine hydrochloride group, weight (p = 0.03), body mass index (p = 0.023), fat mass (p = 0.003), waist circumference (p = 0.005), VAI (p = 0.001), fasting insulin, insulin resistance (homeostasis model assessment of insulin resistance; HOMA-IR), total cholesterol, low-density lipoprotein, triglycerides (TG) and leptin (p < 0.001) decreased whereas adiponectin (p < 0.001) increased in comparison to the baseline values. There was a significant difference in fat mass, VAI, fasting insulin, HOMA-IR, and TG between pyridoxine hydrochloride and control groups following intervention in adjusted models (p < 0.05). The findings suggest that vitamin B6 supplementation may be effective in reducing BMI and improving body composition and biochemical factors associated with obesity.

Trial Registration

Iranian Registry of Clinical Trials Identifier: IRCT20181002041206N1.

The effect of multivitamin-multimineral supplementation on the health status of inbred Wistar and spontaneously hypertensive rat strains

The nutraceutical industry has proliferated in recent years, with the most popular form of supplementation being the multivitamin-multimineral (MVMM) supplement. In the animal health sector, supplement use has also expanded. The objective of this study was to determine the effects of MVMM supplementation, beneficial or otherwise, on the general health status of the spontaneously hypertensive rat (SHR) strain, an animal model used in hypertension research. A commercially prepared MVMM supplement was given tri-weekly via oral dosing for 8 weeks to two groups of seven adult female SHR and Wistar rats. Their corresponding control groups were dosed with deionised water only. Systolic and diastolic blood pressure, fasting blood glucose, growth rate and food and water intake were measured weekly. At the end of 8 weeks, the animals were euthanased and a full blood profile, urine sodium to potassium ratio, blood urea nitrogen levels and total plasma cholesterol was measured for all groups. The results indicated that growth rate was higher for the SHR supplemented group. Supplementation also decreased diastolic blood pressure in both Wistar and SHR groups and increased red blood cell count and decreased total cholesterol in the SHR group. No adverse effects on the general health status of the animals were observed. MVMM supplementation may therefore be useful in aiding growth and delaying the onset of hypertension and its effects. It may also assist in the longevity of the breeding stock of SHR rats.

The Use of Complementary and Alternative Medicine in Hospitalized Patients with Type 2 Diabetes Mellitus in Israel

INTRODUCTION

The use of complementary and alternative medicine (CAM) has been on the rise in recent years in the general population, as well as among patients with chronic diseases such as diabetes mellitus. The aim of this study was to add information regarding the use of CAM in patients with type 2 diabetes mellitus (DM2) in Israel and explore possible interactions between CAM and prescription medication (PM).

METHODS

This is a cross-sectional study based on questionnaires. The study included type 2 diabetic patients who were hospitalized in an internal medicine department at Assaf Harofeh Medical Center, Zerifin, Israel, between December 2013 and December 2014. Possible interactions between CAM and PM were evaluated by a clinical pharmacist and a clinical pharmacologist.

RESULTS

Out of 111 diabetic patients, 23.4% used CAM. There was no significant difference between the consumers and nonconsumers in terms of age, education, income, smoking, or alcohol habits. Only 11 of the 26 CAM consumers informed their physician regarding the use. We found possible drug-herb interactions in 19 of the 26 CAM consumers. A major interaction was found between omega-3 and antiaggregants and was encountered in 7 (26.9%) of the CAM consumers. Other minor and major interactions were found with vitamin E, ginkgo-biloba, co-enzyme Q10, green tea, fenugreek seeds, pyridoxine, and dandelion.

CONCLUSIONS

Since CAM consumption is on the rise, it is desirable to improve our knowledge concerning their potential effects and adverse effects, especially in conjunction with PM. Given the complexity of pharmaceutics in patients with chronic diseases, among them patients with DM, the use of supplementary medicine cannot be ignored.

Role of methylglyoxal in essential hypertension

Altered glucose metabolism due to insulin resistance is a common feature of essential hypertension in humans and in animal models. Elevated endogenous aldehydes in genetic (spontaneously hypertensive rats) and acquired (fructose-induced hypertensive rats) models of essential hypertension may be due to increased production of the reactive aldehyde methylglyoxal, resulting from altered glucose metabolism. Excess methylglyoxal binds sulfhydryl groups of membrane proteins, altering calcium channels and increasing cytosolic free Ca(2+) and blood pressure. It has been demonstrated that methylglyoxal, when given in drinking water to Wistar-Kyoto rats, leads to an increase in kidney aldehyde conjugates, cytosolic free Ca(2+) concentration, decreased serum nitric oxide, renal vascular hyperplasia and hypertension. N-acetylcysteine (NAC) in the diet of these animals prevented hypertension and associated biochemical and morphological changes. NAC normalizes blood pressure by directly binding to excess methylglyoxal, thus normalizing Ca(2+) channels, cytosolic Ca(2+) and nitric oxide. NAC also leads to increased levels of tissue glutathione, a storage form of cysteine. Glutathione acts as a cofactor in the enzymatic catabolism of methylglyoxal. Cysteine and other antioxidants, such as vitamins B(6), C and E, and lipoic acid, prevented hypertension and associated biochemical and morphological changes in both genetic and acquired rat models of hypertension. The antihypertensive effect of dietary antioxidants may be due to an increase in tissue cysteine and glutathione, which improves glucose metabolism and decreases tissue methylglyoxal. A diet rich in these antioxidants may be effective in preventing and controlling hypertension in humans.

Effects of a leucine and pyridoxine-containing nutraceutical on fat oxidation, and oxidative and inflammatory stress in overweight and obese subjects

Leucine stimulates tissue protein synthesis and may also attenuate adiposity by increasing fatty acid oxidation and mitochondrial biogenesis in muscle and adipocytes. Accordingly, the effects of a nutraceutical containing 2.25 g leucine and 30 mg pyridoxine (Vitamin B6) (NuFit active blend) were tested in cell culture and in a clinical trial. 3T3L1 adipocytes were treated with leucine (0.25 mM or 0.5 mM) and/or Pyridoxal Phosphate (PLP) (50 nM or 100 nM) for 48 h. For the clinical trial, twenty overweight or obese subjects received the NuFit active blend or placebo three times/day for 4 weeks without energy restriction. Leucine decreased fatty acid synthase (FAS) expression and triglyceride content in adipocytes, and PLP addition significantly augmented this effect. Administration of NuFit active blend in the clinical trial increased fat oxidation by 33.6 g/day (p < 0.04), decreased respiratory quotient, improved HOMA_IR, reduced oxidative and inflammatory biomarkers (plasma MDA, 8-isoprostane-F_2α, TNF-α, C-reactive protein), and increased the anti-inflammatory marker adiponectin. These data indicate that the NuFit active blend significantly increased fat oxidation and insulin sensitivity, and reduced oxidative and inflammatory stress. Therefore, the NuFit active blend appears to be a useful nutraceutical in the management of obesity and associated co-morbidities.

Vitamin B6: Beyond Adequacy

There is good agreement concerning average requirements and reference intakes for vitamin B6 but less agreement over safe upper levels from supplements. High-dose supplements cause sensory nerve damage. Supplements of vitamin B6 have been advocated for treatment of the premenstrual syndrome, with little evidence of efficacy. There are plausible mechanisms for an antidepressant action and protection against steroid hormone—dependent cancers but no evidence from clinical trials. Pyridoxamine reduces the glycation of proteins and so could be beneficial in preventing the adverse effects of poor glycemic control in diabetes. There are plausible mechanisms for an antihypertensive action but only suggestive evidence from small intervention trials. There is no evidence that supplements of vitamin B6 have any beneficial effect in hyperhomocysteinemia. There is neither a plausible mechanism nor any evidence from controlled trials for any effect of supplements of vitamin B6 in preventing a decline in cognitive function with aging, amelioration of dementia or autism, or improvement of the carpal tunnel syndrome.

Is the anti-hypertensive effect of dietary supplements via aldehydes reduction evidence based? A systematic review

Growing evidence indicates that insulin resistance and oxidative stress are involved in the pathogenesis of essential hypertension. In insulin-resistant states, like obesity and type 2 diabetes, altered glucose metabolism may lead to increased formation of methylglyoxal and other ketoaldehydes. Animal studies have shown that increased levels of endogenous aldehydes may lead to hypertension and oxidative stress. In animal models, the administration of vitamin C, vitamin B6 or alpha-lipoic acid reduced tissue levels of aldehydes, prevented oxidative stress, and lowered blood pressure. The purpose of this review article is to critically evaluate the available evidence for the role of dietary supplements in hypertension treatment.

Prevention of fructose-induced hypertension by dietary vitamins

Essential hypertension in humans may develop through a combination of genetic and environmental factors. Diet has long been under investigation as a potential effector of blood pressure. A diet high in sucrose or fructose can give rise to hyperlipidemia, insulin resistance and hypertension. Insulin resistance, glucose intolerance and oxidative stress are common features of hypertension. If glucose metabolism through the glycolytic pathway is impaired, as in insulin resistance, there will be a build-up of glyceraldehyde, glyceraldehyde-3-phosphate and dihydroxyacetone phosphate with further metabolism to methylglyoxal, a highly reactive ketoaldehyde. Excess aldehydes can bind sulfhydryl groups of membrane proteins, altering membrane calcium channels, increasing cytosolic free calcium, peripheral vascular resistance and blood pressure. The presence of reactive aldehydes can also lead to oxidative stress. Dietary management through lower sucrose or fructose intake and increased consumption of vitamins improves glucose metabolism, lowers tissue aldehydes, increases anti-oxidant capacity and may also prevent hypertension.

Dietary alpha-lipoic acid supplementation lowers blood pressure in spontaneously hypertensive rats

BACKGROUND AND OBJECTIVES

In spontaneously hypertensive rats (SHRs), excess endogenous aldehydes bind sulfhydryl groups of membrane proteins, altering membrane Ca2+ channels and increasing cytosolic free calcium and blood pressure. The thiol compound, N-acetyl cysteine, normalizes elevated blood pressure in SHRs by binding excess endogenous aldehydes and normalizing membrane Ca2+ channels and cytosolic free calcium. The aim of the present study was to investigate whether a dietary supplementation of an endogenous fatty acid, alpha-lipoic acid, another thiol compound that is known to increase tissue cysteine and glutathione, can lower blood pressure and normalize associated biochemical and histopathological changes in SHRs.

METHODS AND RESULTS

Starting at 12 weeks of age, animals were divided into three groups of six animals each. Animals in the Wistar- Kyoto (WKY) rat control group and the SHR control group were given a normal diet, and the SHR-lipoic acid group was given a diet supplemented with lipoic acid (500 mg/kg feed) for the next 9 weeks. After 9 weeks, systolic blood pressure, platelet [Ca2+]i, plasma insulin and liver, kidney and aortic aldehyde conjugates were significantly higher in SHR controls as compared with WKY rat controls and the SHR lipoic acid group. SHR controls also showed smooth muscle cell hyperplasia in the small arteries and arterioles of the kidneys.

CONCLUSIONS

Dietary alpha-lipoic acid supplementation in SHRs lowered the systolic blood pressure, cytosolic [Ca2+]i, blood glucose and insulin levels, and tissue aldehyde conjugates, and attenuated adverse renal vascular changes.