Thursday, May 14, 2020

How Can I Optimize My Immune System?

Given the Covid-19 epidemic, many people are wondering what they can do to keep their immune system running at peak efficiency. I have fielded this question from clients for many years. Here is how I answer them:

To keep your immune system in great shape, you need to focus on 4 areas:
1) Eat healthy. Follow a low glycemic load Mediterranean diet. This includes:
-Lean and healthy protein sources like beans, nuts, chicken and fish. 
-Low glycemic carbohydrates like fruits, vegetables, legumes and whole grains.
-Healthy vegetable fats like olive oil, canola oil, nuts and avocados.

2) Exercise. Cardiovascular exercise should be in the range of 150-180 minutes per week. Also be sure to hit the weights at least twice per week. Keep exercise intensity moderate. Too much exercise can result in overtraining which will actually impair immune function.

3) Get at least 7 hours of sleep each night.

4) Engage in some type of stress reducing program each and every day. This can be meditation, progressive muscle relaxation, deep breathing or yoga. Shoot for at least 10 minutes of focused stress reduction per day.

Carbohydrate Quality And Insomnia

The Study
The relationship between diet and sleep is an area of increasing interest in nutrition research. In this recent study, the impact of carbohydrate quality on risk of incident insomnia was examined in over 50,000 subjects from the Women’s Health Initiative Observational Study. After 3 years of follow-up, women with the highest dietary glycemic index had a statistically significant 16% higher risk of insomnia when compared to women with the lowest glycemic index. Added sugar and refined grain consumption were each independently associated with insomnia while fruits and vegetables were associated with a reduced risk of insomnia. American Journal of Clinical Nutrition 2020; 111:429-39.  

Take Home Message
This is a really interesting study. We all know how important sleep is for our physical and mental health. The idea that what we eat influences how we sleep is not new. However, this is the first study that I have seen that links high glycemic carbs to insomnia. Here is what the researchers think happens: You eat a high glycemic carbohydrate and your blood sugar spikes. Your body releases the counterregulatory hormones adrenaline, cortisol, glucagon and growth hormone to bring your blood sugar back up. Side effects of the counterregulatory hormones released include heart palpitations, tremor, anxiety, irritability and hunger. These can keep you up at night.

This makes a lot of sense and is yet another reason to avoid carbohydrates that spike your blood sugar. Limit high glycemic carbs like bread, pasta, white rice and sugar and focus on low glycemic carbs like fruits, vegetables, whole grains and legumes.

Is Coconut Oil Healthy?

The Study
The health effects of coconut oil is a controversial topic in the field of nutrition. Proponents of certain fad diets claim that coconut oil is good for your heart and aids in weight loss. A recent meta-analysis published in the journal Circulation sheds some light on this controversy. Sixteen articles were included in the meta-analysis and the summary results showed that:

LDL Cholesterol increased by 10.47 mg/dl after coconut oil feeding.

HDL Cholesterol increased by 4.00 mg/dl after coconut oil feeding.

Coconut oil had no impact on body weight.

Take Home Message
I was not particularly surprised by these results. Coconut oil is not a healthy fat. While it may slightly increase HDL (the healthy) cholesterol, it can dramatically increase LDL cholesterol, which increases risk of heart attack and stroke. It has also been shown to have no impact on body weight. Stick with healthy, non-tropical vegetable oils like olive oil or canola oil for your cooking. These oils are high in unsaturated fatty acids, which have been shown in the research literature to improve serum cholesterol levels, improve inflammation and stabilize heart rhythms.

MyPlate Versus The Harvard Healthy Eating Plate

In 2011, the USDA published its latest nutrition recommendations with My Plate. My Plate consists of a simple picture of a plate that visually illustrates what we should be eating at each meal. 

The plate has 4 segments, one for fruits, vegetables, protein and whole grains and a glass of milk on the side. While this was definitely a step forward from the Food Guide Pyramids that preceded My Plate, the recommendations were not based entirely on the latest nutrition research.

In response, Harvard University’s Department of Nutrition published their own healthy eating plate that does a much better job of providing nutrition recommendations. The Harvard version is based on the current research in the field of nutrition and is not subjects to lobbying or political pressures of any kind.

As you can see, the Harvard plate has more detailed recommendations. Let’s take a look at how the two compare:

-Fruits and Vegetables: The MyPlate graphic simply shows that half of your plate should be fruits and vegetables. While this is a great start, the Harvard Healthy Eating Plate goes a step further to mention that variety is important and that potatoes and French fries don’t count as vegetables. These are 2 important distinctions.

-Grains: The MyPlate graphic simply shows that ¼ of your plate should include grains. The Harvard Healthy Eating Plate gives a lot more information here. It recommends to focus on whole grains such as brown rice and to limit refined grains, such as white bread. This is a much better recommendation since distinct types of grains can have very different impacts on health.

-Proteins: The MyPlate graphic simply shows that ¼ of your plate should be filled with protein. The Harvard Healthy Eating Plate provides more detailed instructions to choose fish, poultry, beans and nuts and to limit red meat and cheese and to avoid bacon, cold cuts and other processed meats. These recommendations much better reflect current research evidence on the health effects of protein.

-Milk: The MyPlate graphic shows a glass of milk off to one side of the plate. It recommends dairy at every meal. The Harvard Healthy Eating Plate has a glass of water with the recommendation to drink water, tea or coffee, limit dairy to 1-2 servings per day and to avoid juice and sugary drinks. We don’t need large amounts of dairy in our diet. There is little evidence that a high dairy consumption decreases risk of osteoporosis and very high intakes of dairy can actually be harmful, raising the risk of prostate and ovarian cancer.

Dietary Fat: MyPlate offers no guidance on the consumption of dietary fats. Harvard’s Healthy Eating Plate recommends consuming healthy vegetable oils such as olive oil and canola oil and to limit butter and trans fat. These are important recommendations to include.

Physical Activity: MyPlate offers no message about physical activity. The Harvard Healthy Eating Plate has a little stick figure running in the bottom left with the reminder to stay active. This is a simple yet relevant message about the importance of physical activity in weight maintenance as well as general good health.

Conclusions And Recommendations
Although USDA’s MyPlate is a step forward, the recommendations do not reflect the latest research evidence in the field of nutrition. The Harvard Healthy Eating Plate is a much better guide and should be the reference for those looking to improve their diet and reduce their risk of chronic disease.