Cardiometabolic Health

Cardiometabolic health is a relatively new term that encompasses cardiovascular and metabolic diseases, including type 2 diabetes and metabolic syndrome. Collectively, such conditions are the leading cause of preventable death worldwide. They all share similar risk factors (e.g., overweight/obesity, elevated blood pressure) which can be modified by diet and lifestyle choices. The available evidence indicates that eggs, when consumed as part of an overall healthy diet pattern, do not affect risk factors for cardiometabolic disease. Recent recommendations from the American Heart Association, American College of Cardiology and American Diabetes Association do not limit egg or cholesterol intake, a change from earlier guidance from these organizations. In fact, several global health organizations, including Health Canada, the Canadian Heart and Stroke Foundation, the Australian Heart Foundation and the Irish Heart Foundation, promote eggs as part of a heart-healthy diet.

Given the public health significance of understanding cardiometabolic diseases, research on risk reduction remains an active area of pursuit. For example:

  • A randomized controlled study in people with metabolic syndrome showed that those consuming three whole eggs per day as part of a reduced carbohydrate diet experienced favorable changes in HDL-cholesterol, insulin sensitivity, and other aspects of the lipoprotein lipid profile
  • A randomized controlled weight loss trial in people with diagnosed type 2 diabetes showed improved lipid and glucose markers following consumption of 2 eggs per day for 12 weeks.
  • An egg-based breakfast, rich in protein (35% energy; 26.1 g egg protein), promoted glycemic control in people with type 2 diabetes and pre-diabetes relative to a high-carbohydrate breakfast.

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Can People with Heart Disease Start Eating Eggs Again?

Eggs-One-CrackedFor the past several decades, individuals with heart disease or at high risk for the development of heart disease have been advised to consume <200 mg/day of dietary cholesterol, whereas healthy adults are advised to consume <300 mg/day. Such recommendations are based on the assumption that dietary cholesterol produces harmful increases in blood cholesterol, which increases risk for developing atherosclerosis.

However, this simplistic thinking of A (i.e., dietary cholesterol) increases B (i.e., blood cholesterol) which increases C (i.e., heart disease risk) has been challenged in recent years as advances in diet and cardiovascular disease (CVD) research have revealed that the story is not that straight forward .  We now know that there are other risk factors that influence heart disease risk potentially as much as or more so than elevated blood cholesterol (e.g., inflammation, vascular function, etc.). And with regards to blood cholesterol, not all types of “bad” cholesterol (LDL-cholesterol) may be atherogenic.  Finally, dietary patterns may be more important for influencing CVD risk markers than isolated components, like dietary cholesterol.  And dietary cholesterol may not adversely affect CVD risk factors to the same degree as was previously thought.

Consistent with this thinking is a recently published paper by Dr. David Katz from the Yale University School of Medicine.  His laboratory evaluated 32 patients with documented coronary artery disease who consumed one of three daily breakfast treatments for 6 weeks each: 2 eggs/day; ½ cup of Egg Beaters/day; high-carbohydrate meals such as a bagel, waffles, pancakes, and cereal with milk.  Each treatment period was separated by a 4-week washout.

A number of different cardiovascular risk markers were measured before and after each 6-week intervention period.  Compared to the high-carbohydrate condition, 2 eggs/d did not adversely affect flow-mediated dilatation (an indicator of vascular function), blood cholesterol, blood pressure, or body weight. Further, there were no differences between the 2 egg/day and Egg Beaters conditions.  This despite the fact that cholesterol intake was 742 mg/d in the egg group versus ~200 mg/d in the Egg Beaters and high-carbohydrate breakfast conditions.

This is the first clinical intervention study to evaluate the effects of cholesterol/egg intake on multiple cardiovascular risk markers, including endothelial function, in patients with diagnosed CVD.  The investigators state in the paper that, “Excluding eggs from the diets of patients with CVD as per the AHA dietary recommendations could potentially lead to alternate choices high in starch and sugar, potentially associated with increased CVD morbidity and mortality.”

Although this study was small and relatively short in duration, the results certainly challenge the current thinking around cholesterol restrictions for those with CVD.  As is always the case in nutrition science, additional research is needed to better understand the role of dietary cholesterol in disease risk and progression.

What’s New in the World of Diabetes Research?

Amy-Campbell_2Today’s post comes from Amy Campbell, MS, RD, LDN, CDE. Campbell is a nationally-known dietitian, author, blogger and lecturer specializing in nutrition and diabetes management. As a certified diabetes educator, she was a diabetes educator and program manager at Joslin Diabetes Center in Boston, MA for over 19 years. She is a contributing author to Diabetes Self-Management and Walgreens’ Diabetes & You magazines, where she also serves on the editorial board, and writes a weekly blog for the Diabetes Self-Management website. In addition, she co-authored a book entitled 16 Myths of a “Diabetic Diet”, published by the American Diabetes Association, for which she received both the Will Solimene Award of Excellence in Medical Communication and the 2000 National Health Information Award. Campbell is a Health Professional Advisor for the Egg Nutrition Center, serves on the expert panel for US News’ “Best Diets,” is a Sharecare.com expert and has been an advisor for Calorie King, America’s leading provider of calorie-centric education tools and programs.

The landscape of diabetes research is constantly changing.  As a certified diabetes educator, I admit that I often have a hard time keeping up with the latest developments that are coming (or that have come) down the pipeline. The race for a diabetes cure is still going full throttle, but in the meantime, researchers are busy looking for other ways to treat a chronic condition that currently affects 29 million Americans and that could potentially affect another 86 million who are at risk for developing type 2 diabetes.

A Bionic Pancreas

It sounds so “new-agey,” but researchers at Boston University and Massachusetts General Hospital have created and are currently testing a bionic pancreas for people with type 1 diabetes. People with type 1 diabetes must inject insulin to survive. Most people with type 1 inject insulin anywhere from 2 to 4 times daily, or use an insulin pump to infuse insulin, and check their blood glucose up to 10 times (or more) every day. Obviously, this is a very labor-intensive disease. The bionic pancreas consists of a tiny sensor that’s inserted underneath the skin. This sensor monitors the level of glucose in the tissue and based on that level, can deliver insulin or glucagon via two automatic pumps.  In one instance, twenty adults wore the bionic pancreas and carried a wireless monitor for five days, doing and eating what they wanted, and following no particular schedule.  In another instance, 32 children wore the pancreas for five days while at a camp for children with type 1 diabetes.  The findings? There were 37 percent fewer interventions for hypoglycemia and more than a twofold reduction in time spent in hypoglycemia. Overall, blood glucose levels were significantly improved, particularly during the overnight hours1. The diabetes community is excited about this new technology, but it’s not yet ready for prime-time. The technology needs refining, and larger-scale clinical trials are necessary to show efficacy and safety before the bionic pancreas is suitable for home use.  Stay tuned!

Good Fat, Bad Fat, White Fat, Brown Fat

Chances are you don’t think too much about the type or color of the fat in your body. Well, maybe it’s time to give your fat a second look! When we think about fat, we generally think in terms of having too much of it and ways that we can reduce the amount. But researchers are looking at fat in a different light; specifically, they’re looking at the color of the fat in the body. White fat, which is the most abundant type of body fat, is found throughout the body, and it cushions and protects internal organs. Too much of it can raise the risk of metabolic syndrome, type 2 diabetes and heart disease. Brown fat, on the other hand, is packed with mitochondria, which produce energy for cells. This type of fat actually burns calories to generate heat. It’s found in just a few spots in the body: in the front and back of the neck, between the shoulders, and around the heart and kidneys. Scientists are trying to figure out how to expand the amount of brown fat in the body as a possible treatment for obesity. In addition, newer research shows that brown fat can increase the uptake of glucose from the bloodstream2. Harnessing the dual power of brown fat could prove to be a boon for those with type 2 diabetes, especially as 85 percent of those with type 2 are overweight or obese.

Creating Beta Cells from Stem Cells

We’ve heard a lot about stem cells over the past few years, and while it may seem like the hype has died down a bit, in the field of diabetes, stems cells are hot! A team at Harvard has figured out how to transform embryonic stem cells into beta cells, which are the cells in the pancreas that produce insulin. These cells could then be injected into the pancreas to work their magic. The researchers have developed a method that converts the stem cells into beta cells within 30 days. When the new beta cells were injected into mice with diabetes, they went to work right away and essentially cured the mice’s diabetes within 10 days3. More research is needed, but this methodology will hopefully result in the same effect in humans.

Google’s Contact Lens

Google is more than just a search engine. Google scientists have forayed into the healthcare arena and are busy creating contact lenses that contain special sensors. These sensors can detect levels of glucose in tears. Currently, there are two ways that people with diabetes can monitor their blood glucose levels: with a blood glucose meter, which requires finger sticks, and with a continuous glucose monitor, which involves inserting a sensor underneath the skin that measures interstitial glucose. Both methods are invasive. Google has teamed up with Alcon, a division of Novartis, to develop the contact lenses which will contain a microchip and a low-powered circuit. Information about the glucose level in tears (which will be checked once a second), as well as warnings for impending hypoglycemia, will be sent to a mobile device4. Once again, stay tuned!

 

References

  1. Russell, SJ, El-Khatib FH, Sinha M et al. Outpatient glycemic control with a bionic pancreas in type 1 diabetes. N Engl J Med 2014; 371:313-325.
  1. Olsen JM, Sato M, Dallner OS. Glucose uptake in brown fat cells is dependent on mTOR complex2-promoted GLUT1 translocation. J Cell Biol 2014; 207:365-374.
  1. Pagliuca FW, Millman JR, Gurtler M et al. Generation of functional human pancreatic B cells in vitro. Cell 2014; 159:428-439.
  1. Otis B and Parvis B. (2014, January 16). Introducing our smart contact lens project. Accessed November 18, 2014 from http://googleblog.blogspot.com/2014/01/introducing-our-smart-contact-lens.html.

Nutrition Research Presented at OMED 2014

OMED-pic

ENC wrapped up our conference season this year at the Osteopathic Medical Conference and Exposition (OMED) from October 25-29, in Seattle, WA. We enjoyed interacting with osteopathic physicians and hearing more about interest in nutrition and health during the exhibit booth and during a product forum.

The product forum, titled “Challenging Nutrition Dogma: New Research on Dietary Protein and Health,” presented by Dr. Tia Rains, was well-received and inspired many questions from the audience. Dr. Rains provided a history of dietary trends over several centuries, with a focus on the “fear of fat,” which over the years has resulted in nutrition/health recommendations encouraging a decrease in the consumption of red meat, whole milk and eggs. These recommendations in turn increased the consumption of carbohydrates, specifically simple carbohydrates, but interestingly enough, did not lead to positive changes in the rates of obesity and related chronic illnesses 1.

Dr. Rains then presented an overview of the current body of evidence which suggests that protein, when distributed evenly throughout the day (about 25-30 grams of protein per meal) rather than skewed towards the evening meal, enhances muscle protein synthesis and also has positive associations with improvements in a variety of health conditions such as obesity, diabetes, metabolic syndrome, heart disease, osteoporosis and sarcopenia 2. Dr. Rains concluded the session with practical tips to balance the diet and maximize the benefits of high-quality protein, especially during the morning meal.

We’d love to hear how you have encouraged your clients to think differently about their diet. Please let us know by commenting below!

 

References:

1.  Flegal KM, Carroll MD, Kit BK, Ogden CL. Prevalence of obesity and trends in the distribution of body mass index among U.S. adults, 1999-2010. JAMA. 2012; 307(5):491-497.

2.  Protein summit 2007: exploring the impact of high-quality protein on optimal health. Am J Clin Nutr. 2008;87:1515S-1581S.

Complexity of Individual Variability in Nutrition

close-up-summer-2014-tnToday’s post comes from the Summer Issue of the Nutrition Close-Up, ENC’s newsletter that provides information on current nutrition and research trends and upcoming presentations. Please visit eggnutritioncenter.org to access the current and previous issues of the Nutrition Close-Up.

One size does not fit all when it comes to health. Be it diet, exercise, or prescription medications, what works wonderfully for one person may produce little effect or even the opposite effect in others. This is not surprising given metabolic differences between individuals. I remember observing this first-hand as an undergraduate student in a clinical chemistry course. Each student underwent some basic blood tests, and we compared results across the class. For some tests (e.g., liver enzymes), there was little variability among the students. But in others, there was quite a bit of diversity in results. For example, the blood glucose and insulin responses to an oral glucose tolerance test varied dramatically student to student. The athletic students in the class barely saw much rise in glucose, whereas several of the overweight students saw a dip in glucose below baseline in the late postprandial period (often called reactive hypoglycemia).

In conducting human nutrition intervention trials, I have gained an even greater appreciation for the inter-individual variability that occurs in response to diet and lifestyle interventions. However, this variability is often overlooked or unexplored. Mots scientific papers only report means for the subject population. The standard deviation of the mean can provide some insight into the variance of the dataset, but it does not provide descriptive information, such as the percent of the subject population that responded to a particular treatment. Yet in some cases, inter-individual variability may be important to our understanding of human health.

For example, there is a growing appreciation for understanding inter-individual variability with respect to achieving and maintaining an optimal body weight (i.e., specific genes, environmental factors, epigenetic effects, etc.). McClain et al. recently reported that women with insulin resistance were less successful in adhering to a low-fat weight loss diet and therefore, less likely to lose weight compared to those following a low-carbohydrate diet (1). The investigators hypothesize that higher carbohydrate intakes as part of a low-fat diet negatively influence glucose homeostasis, leading to greater levels of hunger. In an environment where highly palatable food is pervasive, it is easy to quell hunger the minute the urge strikes, compromising diet adherence.

In recent years, the gut microbiome has emerged as another factor that influences responses to diet and lifestyle factors, likely contributing to inter-individual variability in nutrition studies. There is a growing body of evidence that the diversity of bacteria within the gut microbiome is particularly important (2). For example, Santacruz et al. showed greater weight loss in a subset of individuals who showed more marked alterations in the diversity of gut microbiota in response to a calorie-restricted diet (3). Whether there are specific diet-microbiome relationships that further influence weight loss, as well as alter other aspects of physiology, remains to be determined. But based on the research to date, it seems highly likely that we are only beginning to understand the complex set of factors that not only make us who we are, but influence our responses to our environment, including diet.

If there is a theme in this issue of Nutrition Close-Up, it is this concept of “one size does not fit all” when it comes to nutrition. Differences between people, whether on a macro level (e.g., age, race, athletic status, dietary preferences, culture, etc.) or micro level (e.g., genetics, diversity of the gut microbiota, etc.), influence responses to diet. Given the increasing complexity of such differences, it may be decades before research provides solutions to prevent and manage chronic disease. In the near term, keeping abreast and appreciating such differences may be the best we can do.

 

References:

  1. McClain AD, Otten JJ, Hekler EB, Gardner CD. Adherence to a low-fat vs. low-carbohydrate diet differs by insulin resistance status. Diabetes Obes Metab. 2013; 15:87-90.
  2. Erejuwa OO, Sulaiman SA, Ab Wahab MS. Modulation of gut microbiota in the management of metabolic disorders: the prospects and challenges. Int J Mol Sci. 2014; 15:4158-88.
  3. Santacruz A, Marcos A, Warnberg J, Marti A, Martin-Matilas M, Campoy C, Moreno LA, Veiga O, Redondo-Figuero C, Garagorri JM, Azcona C, Delgado M, Garcia-Fuentes M, Collado MC, Sanz Y; EVASYON Study Group. Interplay between weight loss and gut microbiota composition in overweight adolescents. Obesity (Silver Spring). 2009; 17:1906-15.

Applying the Latest Research: Increasing Protein to Benefit Blood Pressure

Data from the NHANES 2005-2008 surveys shows that more than 30% of adult Americans have high blood pressure (HBP).1 It led to 330,000 deaths among Americans in 20072 and is responsible for more than 7 million deaths annually worldwide.1 In 2010, the healthcare costs and productivity losses related to HBP in the US were estimated to be $76.6 billion.1

Blood pressure is affected by many complex factors, and diet plays a key, but, modifiable role in its development. Therefore, it is important that we identify the impact of specific foods and nutrients on blood pressure in order to formulate effective population-based strategies for HBP prevention.  Dietary patterns, such as the Dietary Approaches to Stop Hypertension (DASH) that is characterized by higher intakes of fruits and vegetables and low-fat dairy, have been shown to have blood pressure-lowering effects in clinical trial settings. 3

Evidence from recent reviews4;5 and meta-analyses6;7 suggests that dietary protein consumption may benefit blood pressure, although questions remain regarding the effects of different types of protein. In fact, there are few observational studies (and no clinical trials) that have addressed the differential long-term effects of animal and plant proteins on blood pressure, and the results of the studies are conflicting.8-10
AJH-Logo-300x44In our current study, we used blood pressure data from 11 years in the Framingham Offspring Study to quantify the long-term effects of different amounts and types of protein on blood pressure, as well as the risk of high blood pressure. We used statistical modeling to account for other factors, such as physical activity or smoking habits, in our analyses. After adjusting for these factors, we saw that higher intake of total protein as well as both animal and plant proteins led to lower systolic and diastolic blood pressures at the follow-up exams. And this was true for both normal-weight and overweight (BMI ≥ 25 kg/m2) middle-aged adults.

We also observed that increased intakes of both animal and plant proteins led to about 30-50% reductions in the risk of HBP. Participants in the highest protein intake category (consuming about 103 g/day) had a 40% lower risk of developing HBP over the next 10 or so years. When people who had higher protein diets also consumed more dietary fiber, there was an even greater benefit – they had a 51% lower risk of HBP.

There are relatively few long-term studies of protein and blood pressure. Overall, we found that there was no adverse effect of either animal or plant protein on HBP risk among these middle-aged adults. In fact, those consuming more protein had significant reductions in high blood pressure risk. Thus, if you’re concerned about your clients’ risk of HBP, we found no reason for you to recommend that they avoid foods containing protein. Finally, since there are many different pathways in the body that lead to HBP, and since different foods and nutrients act on different pathways, we think that it is probably important to consume protein from a variety of sources (e.g., eggs, nuts, dairy, poultry, legumes, soy, meat, fish, etc.).

 

References

  1. Vital signs: prevalence, treatment, and control of hypertension–United States, 1999-2002 and 2005-2008. MMWR Morb Mortal Wkly Rep 2011;60:103-108.
  2. Ezzati M, Lopez AD, Rodgers A, Vander HS, Murray CJ. Selected major risk factors and global and regional burden of disease. Lancet 2002;360:1347-1360.
  3. Appel LJ, Moore TJ, Obarzanek E, Vollmer WM, Svetkey LP, Sacks FM, Bray GA, Vogt TM, Cutler JA, Windhauser MM, Lin PH, Karanja N. A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group. N Engl J Med 1997;336:1117-1124.
  4. Altorf-van der Kuil W, Engberink MF, Brink EJ, van Baak MA, Bakker SJ, Navis G, van ‘t V, Geleijnse JM. Dietary protein and blood pressure: a systematic review. PLoS One 2010;5:e12102.
  5. Teunissen-Beekman KF, van Baak MA. The role of dietary protein in blood pressure regulation.Curr Opin Lipidol 2013;24:65-70.
  6. Tielemans SM, Altorf-van der Kuil W, Engberink MF, Brink EJ, van Baak MA, Bakker SJ, Geleijnse JM. Intake of total protein, plant protein and animal protein in relation to blood pressure: a meta-analysis of observational and intervention studies. J Hum Hypertens 2013;27:564-571.
  7. Rebholz CM, Friedman EE, Powers LJ, Arroyave WD, He J, Kelly TN. Dietary protein intake and blood pressure: a meta-analysis of randomized controlled trials. Am J Epidemiol 2012;176 Suppl 7:S27-S43.
  8. Alonso A, Beunza JJ, Bes-Rastrollo M, Pajares RM, Martinez-Gonzalez MA. Vegetable protein and fiber from cereal are inversely associated with the risk of hypertension in a Spanish cohort. Arch Med Res 2006;37:778-786.
  9. Liu K, Ruth KJ, Flack JM, Jones-Webb R, Burke G, Savage PJ, Hulley SB. Blood pressure in young blacks and whites: relevance of obesity and lifestyle factors in determining differences. The CARDIA Study. Coronary Artery Risk Development in Young Adults. Circulation 1996;93:60-66.
  10. Stamler J, Liu K, Ruth KJ, Pryer J, Greenland P. Eight-year blood pressure change in middle-aged men: relationship to multiple nutrients. Hypertension 2002;39:1000-1006.