Monday, January 13, 2020

Glycemic load and inflammatory metabolites


The Study
The glycemic load is a measure of how your diet impacts your blood sugar. A high glycemic load diet causes a lot of dramatic spikes in blood sugar, while a low glycemic load diet has a much easier effect on blood sugar. In this study, 80 subjects consumed a high glycemic load diet for 28 days followed by a low glycemic load diet for 28 days. A variety of metabolic functions were tested after both dietary periods. After the low glycemic load diet, subjects had a significant improvement in metabolites involved with inflammation. American Journal of Clinical Nutrition 2019; 110:984-92.

Take Home Message
This study provides further evidence that dramatic swings in blood sugar can be harmful to our health. Focus on low glycemic load sources of carbohydrate such as fruits, vegetables, legumes and whole grains and be sure to strictly limit refined carbohydrate foods such as bread, pasta, white rice and sugar.

Mediterranean diet and risk of skin cancer


The Study
In this French study, 98,995 women had their diet monitored for a period of 15 years. Each subject was given a score that reflected how well they followed a Mediterranean diet. The score was based on intakes of fruits, vegetables, legumes, cereal products, olive oil, fish, dairy products, meat products and alcohol. Women who most closely followed a Mediterranean diet had a 17% lower risk of skin cancer when compared to women who did not follow a Mediterranean diet. American Journal of Clinical Nutrition 2019;110:993-1002. 

Take Home Message
This is a really interesting study. It is the first I have seen that links a healthy diet to a reduced risk of skin cancer. One potential mechanism is that the Mediterranean diet contains high levels of antioxidant nutrients like beta carotene, retinol, vitamin C and E, folate and vitamin D. These antioxidants may act to reduce damage to DNA. Another potential mechanism is that subjects consuming a Mediterranean diet consume healthier fats like omega 3 fatty acids and monounsaturated fat. These fats may reduce inflammation and in turn, reduce risk of skin cancer. Either way, this study provides more evidence that a Mediterranean diet is a very healthy way to eat.

Akonza Lat Machine Review


Working out at home is a great strategy for anyone who is too busy to get to the gym consistently. You don’t really need all that much equipment, as most body parts can be worked well with a simple pair of adjustable dumbbells. The back is the one body part that is a bit harder to target at home. A machine that focuses on the back is a great idea for any home gym.

That is why the Akonza lat machine is next up for review. This is a lat pull down machine designed for the home gym that has both a high and low pulley. It is available on Amazon.com with free delivery for Prime Members.

Pros
1) This machine is very well built: I have had mine for over 3 years and it looks and works like it did when it was brand new.

2) Not too tall: This is important as some of the machines I looked at were too big for my basement. The Akonza Lat pull down machine is 6 feet, 4.5 inches tall and will fit in most any room in your home.

3) Inexpensive: Currently this machine is on sale at Amazon.com at the very attractive price of $149.97, which includes shipping for Prime Members.

4) Versatile: The machine comes with both a high and low pulley and two attachments. This allows you to add a bunch of exercises for your back, triceps, shoulders and biceps. You can do even more if you add other attachments, which are quite inexpensive.

5) You can put it together by yourself. The directions were not at all complicated, it just took a little time.

Cons
1) The seat is a bit on the small side. This is not a major problem, it just could have been a little bigger.

2) When using the lower pulley for upright rows or bicep curls, the machine is not quite stable and seems like it could tilt backward. This is easily fixed by simply putting one foot on the base of the machine during the upward phase of the exercise. Admittedly, the machine is not designed for these types of exercises, I just like to do them. When using the high and low pulley as intended, the machine is completely stable. 

Do I Recommend the Akonza Lat Machine?
Absolutely. This little gem will turn your basement weight room into a bona fide home gym. The price is right, it is versatile and is built very well. If you are busy, working out at home is critical to working out consistently. Adding just a few pieces of equipment, such as this lat machine, will allow you to replicate the gym experience in the comfort of your own home.

Disclosure: I am not affiliated with the company that makes the Akonza Lat Machine and make no money if you buy it.

Wednesday, November 13, 2019

What is the glycemic index?


The glycemic index was proposed by Dr. David Jenkins at the University of Toronto in 1981 as a way of classifying carbohydrates. Very simply, it gives a score as to how quickly and how severely a carbohydrate will raise your blood sugar. It all starts by feeding a group of subjects 50 grams of glucose (which is pure sugar) and measuring their blood sugar response. This is the baseline or reference measure. Next, the researchers feed the same people 50 grams of another type of carbohydrate, say a baked potato, and measure their blood sugar response once again. 
The glycemic index number is the blood sugar response of that particular carbohydrate relative to the pure glucose reading. For example, the glycemic index of a white baked potato is 78. What that really means is when you eat equal amounts of a white baked potato and pure glucose, the potato results in 78% of the blood sugar response of the pure glucose. This test is repeated for all types of carbohydrate containing foods. A glycemic index of less than 55 is considered low.
Examples of high glycemic index foods: white bread, white rice, rice cakes, crackers, bagels, white potatoes and high sugar foods like cookies, cakes and donuts.
Examples of low glycemic index foods: fruits, vegetables, beans and minimally processed whole grains. 
Eating a lot of high glycemic index foods has been associated with risk of weight gain, type 2 diabetes, heart disease and certain cancers. Therefore, it is a really good idea to strictly limit high glycemic index foods and focus on lower glycemic carbs.


Pistachio nuts and DNA oxidation


The Study
Forty-nine prediabetic subjects ate a healthy diet for 4 months and then ate the same diet but added 2 ounces of pistachio nuts each day for another four months. After the pistachio nut diet, subjects had a significant reduction in the oxidation of their DNA. The pistachio nut intervention also had a positive impact on gene expression of telomeres. American Journal of Clinical Nutrition 2019; 109:1738-45.

Take Home Message
Telomere attrition is a natural process that is recognized as one of the hallmarks of aging. Nuts have long been associated with improved health in the research literature. In particular, they have been shown to reduce risk of type 2 diabetes, heart disease and all-cause mortality. This study uncovers some of the potential mechanisms by which nuts improve our health. A reduction in DNA oxidation and the shortening of telomeres are two processes associated with aging and illness. In this study, pistachio nut consumption had a positive impact on both. I always recommend a serving or two of nuts each day for my clients.

Soda and risk of type 2 diabetes in young adults


The Study
In this study, 4,719 men and women aged 18-30 had their soda consumption measured repeatedly and were followed for 30 years. By the end of the follow-up period, 680 of the subjects developed type 2 diabetes. Each daily serving of soda sweetened with sugar was associated with a statistically significant 6% higher risk of developing type 2 diabetes. Diet soda was not associated with an increased risk of type 2 diabetes in these subjects. American Journal of Clinical Nutrition 2019;110:733-41.

Take Home Message
It is a really good idea to strictly limit sugar sweetened beverage consumption. Even a single portion per day was associated with a significant increase in risk of type 2 diabetes in this investigation. While diet soda was not associated with diabetes risk, you don’t want to simply substitute diet soda for regular soda, there are much better choices. While an occasional diet soda is fine, focus your beverage choices on water, naturally flavored club soda or decaf coffee or tea.

Book Review: Whole 30


Next up for review is Whole30: The 30 day guide to total health and food freedom. There are 2 authors; Dallas Hartwig, who is a licensed physical therapist and Melissa Hartwig.

Introduction
The goal of this book is to teach you how to reset your health by avoiding all foods that the authors consider unhealthy for 30 days. After the thirty days are over, you re-introduce one food group at a time to see how you physically respond to it. You then decide what you can safely eat and what you should avoid going forward. The book is 422 pages. It is very well written. The authors have a very motivating style of writing and I enjoyed reading this book.

5 Things I Really Liked About Whole 30
1) I really like that this book has you strictly limit refined carbohydrates like bread, white rice, pasta and sugar. I strongly believe that a stable blood sugar is the path to weight loss and greater health. Avoiding these foods will make it much easier to maintain a stable blood sugar.

2) I agree with the authors idea that inflammation is behind most chronic disease. 

3) This book provides a ton of recipes. Cooking for yourself is critical to improving your diet. These recipes make it much easier to do so.

4) I really like the meal template. Combining a source of protein, fat and carb at each meal is critical to maintaining a stable blood sugar.

5) The section on eating out at restaurants is really well done. Eating meals outside of the home is a major challenge to anyone looking to improve their diet. This section gives you some good tips to stay on course when dining out.

5 Things I Didn’t Agree With in Whole 30
1) I do not understand the recommendation to limit nuts. Nuts have consistently been shown in the research literature to improve health (References 1 and 2). They are loaded with protein, healthy fat, fiber, and other micronutrients. They are not in the slightest bit unhealthy.

2) Similarly, I don’t agree with the idea that whole grains are unhealthy and promote inflammation. Whole grains have been shown in the research literature to reduce risk of heart disease, certain cancers, diabetes and inflammatory mortality (References 3-6). They are a very important part of a healthy diet.

3) I also don’t agree with the recommendations to avoid legumes. Legumes (like beans and lentils) are nutritional powerhouses. They are loaded with fiber and are an excellent choice of low glycemic load carbohydrate. They are a very good source of healthy vegetable protein and are packed with micronutrients. I don’t understand why the authors would think these are unhealthy.

4) While the book recommends avoiding some very healthy foods like nuts, whole grains and legumes, it also recommends some questionable ones. You can eat potatoes and drink fruit juice on this plan. These foods are very high on the glycemic index/glycemic load scale and should be strictly limited in order to stabilize blood sugar.

Similarly, coconut oil, butter and red meat are given the green light as well. These are unhealthy sources of fat and protein and should be strictly limited.

5) Once the 30 days are up, I feel that the recommendations are a little too open ended. The authors advise adding one food back at a time and then to see how you feel. After you add the food back to your diet, you then decide if and how often you want to have it. I feel like there could have been a bit more guidance about what foods will promote (or hurt) long term health going forward.

Is Whole 30 Worth Reading?
Absolutely! This book gets a lot right. The Whole 30 plan limits refined carbohydrates like white bread, white rice, sugar and pasta. It helps to stabilize the blood sugar by recommending a source of protein, fat and carb at every meal. I would make just a few small changes: nuts, whole grains and legumes are very good for you and don’t need to be avoided. Saturated fats like coconut oil, butter and red meat should be strictly limited. One last thing, you don’t just want to eat healthy for 30 days and then add a lot of the unhealthy stuff back in. Although it is admittedly difficult, the goal is to eat healthy for the rest of your life.

References
1) Hu FB, Stampfer MJ, Manson JE, et al. Frequent nut consumption and risk of coronary heart disease in women: prospective cohort study. British Medical Journal 1998; 317:1341-45.

2) Jiang R, Manson JE, Stampfer MJ, et al. Nut and peanut butter consumption and risk of type 2 diabetes. Journal of the American Medical Association 2002; 288:2554-60.

3) Liu S, Stampfer MJ, Hu FB, et al. Whole grain consumption and risk of coronary heart disease: results from the Nurses’ Health Study. American Journal of Clinical Nutrition 1999; 70:412-19.

4) Schatzkin A, Mouw T, Park Y, et al. Dietary fiber and whole grain consumption in relation to colorectal cancer in the NIH-AARP diet and health study.  American Journal of Clinical Nutrition 2007; 85:1353-60.

5) Sun Q, Spiegelman D, Van Dam RM, et al. White rice, brown rice, and risk of type 2 diabetes in U.S. men and women. Archives of Internal Medicine 2010; 170 (11):961-69.

6) Jacobs DR, Andersen LF, Blomhoff  R. Whole grain consumption is associated with a reduced risk of noncardiovascular, noncancer death attributed to inflammatory diseases in the Iowa Women’s Health Study. American Journal of Clinical Nutrition 2007; 85:1606-14.