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Carbohydrate Restriction for Type 2 Diabetes

Researchers affiliated with Virta Health (San Fransciso, California) have published results from a year-long study of its comprehensive care program that supports people with type 2 diabetes (T2D) as they maintain nutritional ketosis with a low-carbohydrate diet. Nutritional ketosis is defined as a serum beta-hydroxybutyrate (BOHB) level between 0.5 and 3.0 mmol/[L.sup.-1] The program includes education about diabetes, managing carbohydrate restriction while consuming protein in moderation and increasing fat intake, and behavior change techniques. Nutritional programs were individualized with the goal of maintaining nutritional ketosis with satiety. Patients were advised to consume a variety of fats, including omega-3 fatty acids (EPA and DHA), omega-6 fatty acids (linoleic acid), monounsaturated and saturated food sources. In addition to supplemental omega-3 (up to 1000 mg/day), a multivitamin and vitamin D3 (1000-2000 IU) were recommended.

Regular communication between patients and the health care team is a key part of this program. Upon admission, patients received digital biomarker tracking tools, including a cellular-connected weight scale, a finger-stick blood glucose and ketone meter, and a blood pressure cuff for those with hypertension. Participants provided ketone measures daily and glucose measures one to three times a day so that medical providers, trained in nutritional ketosis, could adjust diabetes medications as needed. Medication status was reviewed weekly. In addition, patients had daily support from health coaches via text messaging to address any questions or concerns and from peers via online communication.

The researchers have published three studies so far about this program. All three studies follow a group of 262 volunteers with T2D (mean age 54, SD 8 years; mean body mass index 41; 66.8% women), recruited from greater Lafayette, Indiana. Most subjects were taking at least one diabetes medication (234/262, 89.3%). "Exclusion criteria included advanced renal, cardiac, and hepatic dysfunction, history of ketoacidosis, dietary fat intolerance, or pregnancy or planned pregnancy."

The first study, published in 2017, sought to determine whether it made a difference if participants received the education content during weekly on-site sessions or via web-based recorded videos. Patients were able to self-select their preference. In addition, T2D-related biomarkers were recorded at baseline and at ten weeks. At 10 weeks, 238 participants remained. One person withdrew in the first 70 days because of diarrhea due to fat intolerance; no information was given on the others.

Both the on-site and the remote groups showed significant improvement in biomarkers, indicating that both education venues were effective. HbA1c levels (a measure of average blood sugar) significantly declined. Only 52/262 (19.8%) had an HbA1c level of <6.5% at baseline, compared to 147/262 of the patients (56.1%) after 10 weeks. In addition, 133/234 individuals had one or more diabetes medications reduced or eliminated. During those 10 weeks, participants maintained consistent carbohydrate restriction, indicated by a mean BOHB of 0.6 (SD 0.6) mmol/[L.sup.-1].

A second study, published in 2018, looked at results of the Virta intervention after one year, using data from the same cohort. HbA1c, weight, and medication use were the primary outcomes. Fasting serum glucose and insulin, HOMA-IR, blood lipids and lipoproteins, liver and kidney function markers, and high-sensitivity C-reactive protein (hsCRP) were secondary outcomes. In addition, the Virta cohort was compared to a control group of 87 patients with T2D, who were counseled about nutrition, lifestyle, and self-management as part of a local diabetes education program with registered dietitians (usual care).

Eighty-three percent (n=218) of the original Virta enrollees (n=262) completed the full year. After one year, HbA1c had declined from a baseline of 7.6 [+ or -] 0.09% to 6.3 [+ or -] 0.07%, (P<1.0 x [10. sup.-16]), and weight declined 13.8 [+ or -] 0.71 kg (P<1.0 x [10.sup.-16]). In addition, 94% of patients who were prescribed insulin either reduced or stopped their insulin use, and sulfonylurea use was discontinued in all patients. The usual-care, control group had no significant changes in biomarkers or in T2D medication use.

Despite the low-carb, high-fat diet, measures for liver, kidney, and thyroid function showed either improvement or no change. Also, no Virta patients experienced ketoacidosis or episodes of hypo- or hyper-glycemia that required assistance. The authors say, "The absence of hypoglycemic events requiring assistance despite relatively tight glucose control may be due to the careful medical provider prescription management, especially rapid downward titration of insulin and sulfonylurea preventing hypoglycemia following dietary changes."

Despite the increased dietary fat consumed by the Virta patients, dyslipidemia and markers of inflammation and liver function were generally improved at one year. A third study, published in Cardiovascular Diabetology, focused on the intervention's effect on cardiovascular disease risk biomarkers in the 218 participants who remained. All measured biomarkers, except LDL-C, showed improvement: "Intention-to-treat analysis (% change) revealed the following at 1-year: total LDL-particles (LDL-P) (-4.9%, P=0.02), small LDL-P (-20.8%, P=1.2 x [10.sup.-12]), LDL-P size (+1.1%), ApoB (-1.6%), ApoA1 (+9.8%), ApoB/ApoA1 ratio (-9.5%), triglyceride/HDL-C ratio (-29.1%), large VLDL-P (-38.9%), and LDL-C (+9.9%)." The authors note that LDL-C, regarded as a CVD risk factor, has also been inversely correlated with mortality in two large prospective studies. Blood pressure, hsCRP, and white blood cell count also declined. Carotid intima media thickness (cIMT) remained unchanged. The usual-care control group showed no significant changes.

The authors give several limitations of these studies, notably, the lack of randomization between the Virta and usual care groups. Also, the amount of attention and support given to patients in the Virta group was much greater--which, in itself, could be a factor. Participants were primarily Caucasians living in the Midwest; the results cannot be generalized to other regions or races. Finally, measuring cardiovascular biomarkers is not the same as looking at actual CVD events or deaths: "The study was not of sufficient size and duration to determine significant differences in CVD morbidity or mortality."

Virta Health, "founded in 2014 with the goal of reversing type 2 diabetes in 100 million people by 2025," has several short videos about this program on YouTube as well as information on its website, The program emphasizes that it works with patients' primary care practitioner in offering this care.

Bhanpuri NH, et al. Cardiovascular disease risk factor responses to a type 2 diabetes care model including nutritional ketosis induced by sustained carbohydrate restriction at 1 year: an open label, non-randomized, controlled study. Cardiovasc Diobetol. 2018;17:56

Hallberg SJ, et al. Effectiveness and Safety of a Novel Care Model for the Management of Type 2 Diabetes at 1 Year: An Open-Label, Non-randomized, Controlled Study. Diabetes Ther. 2018;9: 583-612.

McKenzie AL, et al. A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes. JMIR Diabetes. 2017;2(1):e5.

Chocolate and CVD

Chocolate, made from the seeds of the cocoa tree (Theobroma cacao), is a rich source of flavonoids that benefit the cardiovascular system, according to multiple studies. An Italian review and meta-analysis of 16 studies with a total of 344,453 participants reported that most of the studies found "a significant reduction of CVD risk in association with higher levels of chocolate intake after adjustment for potential confounders, including age, physical activity, BMI, smoking status, dietary factor, education, and drug use." The meta-analysis reported an overall risk ratio of cardiovascular disease for the highest vs. the lowest category of chocolate consumption as being 0.77 (95% confidence interval [CI], 0.71-0.84; P= 0.000). In addition, the meta-analysis showed chocolate consumption was associated with reduced risk for coronary heart disease (47%), stroke (30%), acute myocardial infarction (22%), and heart failure (17%). The data in the reviewed epidemiological studies was derived from food frequency questionnaires or self-reports. The type(s) of chocolate (milk, dark, white) providing benefit was unclear from the data.

A 2018 review, led by Sergio Davinelli, reported on the many known effects of cocoa's flavonols and suggested that using cocoa with omega-three fatty acids might enhance the cardiovascular benefits synergistically. Flavonol-rich cocoa increases antioxidant activity. The flavonols also increase bioavailability of nitric oxide (NO) in the endothelium, preventing leukocyte adhesion and migration, smooth muscle cell proliferation, platelet adhesion, and aggregation. Moreover, increased NO bioavailability promotes relaxation of vascular smooth muscle cells, leading to vasodilation. Cocoa flavonols may also reduce inflammation by suppressing the production of inflammatory eicosanoid metabolites. Davinelli et al say that "the ongoing Cocoa Supplement and Multivitamin Outcomes Study (COSMOS), which aims to determine the efficacy of a flavonol-rich cocoa using a 5-year randomized trial among 18,000 healthy men and women, may provide definitive evidence on the health benefits of cocoa on cardiovascular outcomes."

People who are consuming chocolate for its health benefits may want to check the website by As You Sow. This non-profit organization strives to promote environmental and social corporate responsibility. Since 2014, As You Sow has commissioned independent state-certified laboratories to measure lead and cadmium levels in chocolate products sold in California. Most products (96 of 127 tested products) have higher lead and/or cadmium levels than allowed by the California Safe Drinking Water and Toxic Enforcement Act of 1986. The organization works with manufacturers to reduce heavy metal content.

Contamination can come from several sources. Pervasive industrial pollution contaminating soil and water used in growing cacao is one source, but growing practices that use pesticides (lead and cadmium), phosphate fertilizers (cadmium), and sewage sludge (lead and cadmium) can also affect cocoa's heavy metal content. Equipment used to ship and process the cocoa beans is also an important source of contamination.

As You Sow lists results from tested chocolate products at its website:

Davinelli S, et al. Cardioprotection by Cocoa Polyphenols and [omega]-3 Fatty Acids: A Disease-Prevention Perspective on Aging-Associated Cardiovascular Risk. J Medicinal Food. 2018; 21(10): 1060-1069.

Gianfredi V, et al. Can Chocolate consumption reduce cardio-cerebrovascular risk? A systematic review and meta-analysis. Nutrition. 2018;46:103-114.

Kefir for Metabolic Diseases

Kefir, which originated in the northern area of the Caucasus Mountains, is a traditional fermented milk product. Kefir grains, used to make the beverage, consist of a symbiotic mix of lactic and acetic acid bacteria (eg Lactobacillus, Lactococcus, Leuconostoc, and Streptococcus spp.) and yeasts (eg Kluyveromyces, Saccharomyces, and Torula).

A 2018 review article from Brazil suggests that kefir may provide benefits for people with cardiovascular and metabolic diseases. Kefir has antioxidative properties, according to multiple studies. Some kefir bacteria synthesize antioxidant enzymes, such as peroxidase, superoxide dismutase, and glutathione reductase, as well as producing other substances that reduce oxidative stress. Daily consumption of kefir has also produced immunomodulatory and hypocholesterolemic effects.

Experiments with spontaneously hypertensive rats found that kefir, consumed for at least 30 days, produced a significant reduction in blood pressure levels as well as reduction in tachycardia and left ventricular hypertrophy, characteristic of these rats. Several species of Lactobacillus--L. fermentum, L. coryniformis, L. gasseri, L. helveticus, L. paracasei, and L. lactis--are among the probiotic bacteria found in kefir grains that have these hypotensive effects. Animal experiments have also shown that kefir restores balanced parasympathetic and sympathetic activity to the heart.

The microbial composition of kefir grains varies from region to region. Brazilian kefir grains, for example, contain Lactobacillus kefiranofaciens, Bifidobacterium, and the yeast Candida kefir. A Chinese study that analyzed kefir grains taken from three Tibetan households determined Pseudomonas sp. Leuconostoc mesenteroides, L. helveticus, L. kefiranofaciens, Lactococcus lactis, Lactobacillus kefiri, Lactobacillus casei, Kazachstania unispora, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Kazachstania exigua to be the primary organisms. I don't know if the kefir beverages sold in US supermarkets have anything close to the microbial complexity or composition of traditional sources. The Brazilian authors say that "additional studies are required to verify if milk fermented by kefir grains from different origins and production processes could have similar beneficial effects."

Pimenta FS, et al. Mechanisms of Action of Kefir in Chronic Cardiovascular and Metabolic Diseases. Cell Physiol Biochem. 2018;48:1901-1914.

Zhou J, et al. Analysis of the microflora in Tibetan kefir grains using denaturing gradient gel electrophoresis. Food Microbiology. 2009;26:770-775.

Hypertension and "Om"

The meditative practice of chanting "Om" reduces blood pressure (BP), according to studies by Indian researchers. A 2018 study, involving 50 people with hypertension, showed blood pressure reduction with five minutes of Om chanting. The participants, between ages 40-60 years old, had poorly controlled, mild or moderate hypertension despite being on pharmaceutical treatment. After recording baseline BP, a facilitator instructed each subject to gently close their eyes, inhale gently and deeply and then produce the sound "Omm..." as they exhaled, concentrating on the sound and its effect on their belly. This chanting continued for five minutes, after which blood pressure was re-taken. Mean blood pressure dropped 14 mmHg for systolic BP (P < 0.001) and 5 mmHg for diastolic (P < 0.05). Mean pulse rate also declined by six beats.

The authors report that Om chanting stimulates the vagus nerve and deactivates the limbic system. The resulting parasympathetic predominance and cortico-hypothalamo-medullary inhibition may explain why the chanting had a greater effect on systolic BP, which reacts to stress, and less effect on the diastolic, which indicates arteriolar resistance.

Blood pressure also declined in a 2016 randomized study, involving 40 women, age 50-60 years, with blood pressure values of 120-179/[less than or equal to]109 mmHg. Twenty women chanted Om once a day as a group at Sattva Cultural Space and Research Centre for six months while the remainder acted as the control. Systolic and diastolic pressure, pulse rate, as well as depression, anxiety and stress measures decreased significantly in the Om group.

A 2011 study, led by Bangalore G. Kalyani, used functional magnetic resonance imaging (fMRI) to track neurohemodynamic effects of chanting Om compared to making an "sss" sound or simply being in a state of rest. Nine healthy men took part in the study. They were taught to chant Om "without distress and interruption," sounding the vowel (O) for five seconds and continuing into the consonant (M) for the next 10 seconds. After a baseline high-resolution structural brain scan, echoplanar scans were taken as the participants engaged in 15 seconds of Om chanting, 15 seconds of rest, and 15 seconds of making an "sss" sound for a total of ten minutes. Although it required the same exhalation length, the "sss" sound, unlike Om, does not produce a vibration around the ears that is thought to affect the auricular branch of the vagus nerve.

Compared to the rest periods, the "sss" sound did not produce any significant activation/deactivation in any brain area. Om, however, produced significant deactivation in the amygdala, anterior cingulated gyrus, hippocampus, insula, orbitofrontal cortex, parahippocampal gyrus, and thalamus.

According to yoga practice, Om represents "the force behind all thoughts, and chanting or thinking about Om will cause quiet mental state." Possibly, the effect of Om chanting may be stronger among people who ascribed to Vedic spirituality. Or, it could be that the vagus nerve, responsible for parasympathetic control of the heart, is just truly responsive to sound vibrations.

Amin A, et al. Beneficial effects of OM chanting on depression, anxiety, stress and cognition in elderly women with hypertension (abstract). Indian J Clin Anatomy and Physiol. July-september 2016;3(3):253-255.

Arora J, Dubey N. Immediate benefits of "Om" chanting on blood pressure and pulse rate in uncomplicated moderate hypertensive subjects. National J Physiol, Pharmacy, and Pharmacology. 2018.

Kalyani BG, et al. Neurohemodynamic correlates of 'OM' chanting: A pilot functional magnetic resonance imaging study. International J Yoga. Jan-Jun 2011; 4(1): 3-6.

briefed by Jule Klotter
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Title Annotation:low carbohydrate diet for type 2 diabetes, chocolates to prevent cardiovascular diseases, health benefits of kefir
Author:Klotte, Jule
Publication:Townsend Letter
Date:May 1, 2019
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