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Fruit Drinks, Energy Drinks and Heart Disease

Vitamin D Deficiency, Obesity and Cardiometabolic Risk: Is there any Relationship?

Until now we have been talking about several different risk conditions like adiposity, cardiovascular disease, diabetes, osteoporosis, hormone imbalance, vitamin D deficiency and other related disorders. After spending billions of dollars in medical research, we have collected huge amount of data and a wealth of information. It is time to get serious and make use of this information. Let me put it this way, we have collected most of the pieces of a big puzzle and now it is time to put together these pieces and complete the puzzle. We all recognize that our bodies do not work in isolation and so we need to look at all the body systems together as one system, which controls how we live our lives. I believe we may already have answers to so many questions. We may not have to spend more money into research to collect more data, which might create more confusion for us and more challenge to analyze all that new data. We could keep debating over what we should or should not do, but for now, since I titled this piece with a focus on role of vitamin D in obesity and cardiometabolic risk, let me discuss how vitamin D is emerging as a strong candidate to consider when we accumulate few extra pounds in our bodies, especially around our abdomen.

Now that holidays are over and New Year has begun, many of us are busy exercising and trying to shed those extra pounds we gained enjoying cookies and treats. Most of us have been indoors by the fireplace, especially in the Northwest where I live and where sun is known to be a luxury. Of course I do not have any reason to envy those who are in Midwest, especially after reading the newspaper this morning to see how most of the country is under the grip of winter chills with temperatures as low as 52 below zero in the Midwest. My point is that we have not had a chance to get out and get some sunlight so we could make some vitamin D. We all know how important is, sun exposure for endogenous production of vitamin D in the skin. There is evidence now that vitamin D is implicated in the cardiovascular morbidity and mortality, in addition to its role in musculoskeletal health. There is also some evidence that vitamin D deficiency is associated with obesity. We could argue that this association is indirect because obese individuals are less active and thus they get less sunlight exposure. However, some studies have shown that since vitamin D is fat soluble and therefore stored in fat tissue, which makes it less bio-available when there is more fat tissue. Obesity has been shown to have connection with insulin resistance and metabolic syndrome. Does that mean there is a link between insulin resistance, metabolic syndrome and vitamin D deficiency? The answer is yes, because some computed tomography imaging studies combined with measurements like BMI and waist circumference have suggested that vitamin D may be related to variation in regional adiposity and thus could be implicated in insulin resistance and metabolic syndrome, thereby connected indirectly with all biochemical mechanisms including inflammatory pathways leading to conditions like diabetes, atherosclerosis and coronary heart disease.

A recent study by Susan et al. that appeared in the January 2010 issue of Diabetes journal has shown that vitamin D deficiency is related with increased BMI; there is an inverse relation of 25-hydroxyvitamin D [25(OH)D] with subcutaneous and abdominal fat even in individuals who are lean with low BMI; and finally there is strong correlation between 25(OH)D and markers of insulin resistance, especially connected with abdominal adiposity. One could argue that some other factors like limited physical activity or low vitamin D intake may have caused the observed correlations, but the good thing is that this study took into consideration those confounders too as their subjects were all young to middle aged, with little comorbidities and low medication use. The study showed independent association between subcutaneous fat or visceral fat with 25(OH)D. It is also discussed that only differences in sunlight exposure are not enough to account for vitamin D concentration differences between obese and non-obese individuals. I will not go into too many details here about biochemical mechanisms that have been discussed to explain possible association of vitamin D with adiposity. Several findings have suggested multiple mechanisms involved with good evidence that vitamin D deficiency is implicated in obese individuals and thus connected with insulin resistance and related disorders.

So, for now the message is, let us watch out for those extra calories that we throw into our bellies. I am not asking you to stop enjoying cookies and left over treats from holidays, but what I am saying is that it is time we pay more attention to what we eat, how much we eat and what we do to metabolize all the extra calories we consume. Let us take good care of our waistline and if we see someone with a big waist, let us help them by making them aware of how vitamin D deficiency could be something to look for. How do we know we are vitamin D deficient? Well- there are tests available that can help us determine the vitamin D levels in our body and how much supplement do we need to replenish healthy levels. To make our life easy, there is a dried blood spot test available, which involves convenient home collection of sample, which is simply mailed to the laboratory and analyzed. You do not have to get out of home, get an appointment with a lab or phlebotomist, drive across town or take off from work. Does that not sound good? Feel free to email me (skapur@zrtlab.com) if you wish to share some thoughts or need more information. Let us continue this discussion.

Insulin and triglyceride levels after different breakfast meal challenges – measurement in dried blood spots (DBS)

I wish to share with my readers an interesting study that the ZRT research team presented recently at the 7th Annual World Congress on Insulin Resistance in San Francisco and won a Bronze Award among appox. two hundred abstracts submitted for competition.

Postprandial insulin and triglyceride (Tg) levels have been suggested as potential clinical tools to help identify individuals at high risk of atherosclerosis and coronary heart disease. Published studies have used a variety of meal types. We investigated the effects of 5 different breakfast meals on postprandial insulin and triglyceride levels, to see if meal type elicited different responses and to help identify a suitable protocol for routine risk assessment.

Blood spots were obtained by finger stick from 19 healthy volunteers after a overnight fast and then 2 hours after eating each of 5 breakfast meals. At least 1 week elapsed between each test meal. After collecting blood spots on a filter paper, they were allowed to dry and stored at room temperature until analysis. 6-mm disks were punched from the dried blood spots into 96-well plates; insulin was assayed using modified serum ELISA assay kits after extraction with extraction buffer, and Tg were assayed using an enzymatic assay following extraction with methanol . The DBS assay correlates highly with simultaneous serum testing, demonstrated in a previously published study. The serum/DBS correlation coefficients for insulin and Tg in that study were r=.93 and r=.91 respectively.

For statistical analysis, insulin and Tg levels were categorized as either normal or abnormal; within the “normal” classification, they were further categorized into “optimal” or “non-optimal”. For insulin, values >15 µIU/mL were “abnormal” and >8 µIU/mL were “non-optimal”, while for Tg, >150 ng/mL was “abnormal” and >100 ng/mL “non-optimal”. Using a Wilcoxon paired sign test, outcomes for each meal were compared to all other meals.

Insulin levels at 2 hours showed a difference in response depending on meal composition. Postprandial insulin appears to correspond to overall carbohydrate content; more abnormal/non-optimal results were seen after meal 4 (highest carbohydrate content) and the fewest abnormal/non-optimal results were seen after meal 2 (lowest carbohydrate content), despite the fact that meal 2 had the highest fat content and the most overall calories. Sustained, higher than optimal insulin levels 2 hours after eating could represent an additional cardiometabolic risk factor, even in individuals whose fasting levels are normal. Dietary choices may therefore increase a person’s chances of postprandial dysmetabolism. In non-diabetics, high postprandial insulin levels are an independent risk factor for coronary artery disease.

Tg levels at 2 hours did not differ significantly between meals, although only about half the values seen were in the normal range. We know from the literature that Tg levels tend to peak around 4 hours postprandially, and in our subjects Tg was still rising after the 2 hour measurement. A 4-hour sample may have elicited a between-meal difference, but compliance issues with collecting a sample 4 hours after eating might preclude postprandial Tg as a routine clinical test.

Convenient, in-home collection of DBS offers a simple tool to research the phenomenon of postprandial dysmetabolism. Assessment of DBS insulin levels 2 hours after a meal may help identify risk in individuals whose fasting levels are normal, and can indicate whether routine dietary choices are exposing them to greater risk than necessary.

Following is the abstract of the study that was presented at the conference.

Insulin and triglyceride levels after different breakfast meal challenges – measurement in dried blood spots (DBS)

Sonia Kapur, Margaret Groves, David Zava, Sanjay Kapur
ZRT Laboratory, Beaverton, Oregon, USA.

The metabolic conditions that predispose individuals to atherosclerosis are thought to be a postprandial phenomenon, termed “postprandial dysmetabolism”. In non-diabetics, high postprandial insulin and triglycerides are independent risk factors for coronary artery disease and cardiovascular events.

Pre- and postprandial serum testing for insulin and triglycerides is inconvenient for patients and practitioners, limiting routine application of these tests and their use in large scale clinical studies.

We developed finger stick DBS tests for insulin and triglycerides that correlate highly with venous serum values (r=.93 and r=.91 respectively), and evaluated these analytes in DBS from 19 healthy volunteers after an overnight fast, before and 2 hours after eating 5 different breakfast meals.

Meals consisted of: 1) glazed donuts, fruit smoothie; 2) boiled eggs, sausages, 2% milk; 3) bagel, cream cheese, boiled egg, 2% milk; 4) pancakes, syrup, tea with cream/sugar; 5) oatmeal, almonds, apple, skim milk.

Postprandial insulin levels >8 µIU/mL were classified as “non-optimal” while >15 µIU/mL were “abnormal”; triglyceride levels >100 ng/mL were “non-optimal” and >150 ng/mL “abnormal”.

For insulin, meal 2 (lowest carbohydrate, highest protein) produced the best (fewer abnormal/non-optimal) postprandial results and meal 4 (highest carbohydrate, lowest protein) the worst (more abnormal/non-optimal) postprandial results. For triglycerides, no meal differed significantly from the others in the number of abnormal or non-optimal classifications.

The convenience of in-home collection and analyte stability offer much wider scale use of the DBS tests for routine clinical assessment and large scale epidemiological studies of postprandial dysmetabolism.

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Testosterone and Men's Health

New Definition of Metabolic Syndrome

Did you know the new definition of Metabolic Syndrome? Did you know that waist circumference is now one of five criteria that physicians can use to diagnose metabolic syndrome?

The ATP III guidelines earlier did not consider the waist circumference as an important criteria, to diagnose metabolic syndrome, but a recent statement published online on October 5, 2009 in Circulation actually is a step forward to streamline the use of abdominal obesity in determination of risk of developing metabolic syndrome. The new statement on metabolic syndrome is a combined effort by International Diabetes Federation (IDF), the National Heart, Lung, and Blood Institute (NHLBI), the World Heart Federation, the International Atheroschlerosis Society, and the American Heart Association (AHA).

According to the new definition, people with any three of the following five criteria are considered to have the metabolic syndrome:
1. Increased waist circumference (population and country specific cut points)
2. High triglycerides (≥150 mg/dL)
3. Reduced HDL cholesterol (<40 mg/dL for males and <50 mg/dL for females)
4. Elevated blood pressure (Systolic ≥130 mm Hg and/or diastolic ≥ 85 mm Hg
5. Increased fasting glucose ≥ 100 mg/dL