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.

https://doi.org/10.1161/CIRCULATIONAHA.119.043052

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.

Does weight gain change your brain’s response to high sugar/high fat foods?

The Study

In this fascinating study, 67 subjects were given milkshakes containing varying amounts of fat and sugar while undergoing a brain MRI. Thirty-six of these subjects had a 10% or greater increase in their BMI in the previous 2 years. Thirty-one of these subjects were weight stable in the previous 2 years. The subjects who had gained weight showed a decreased responsivity in brain regions associated with taste and reward processing when consuming milkshakes high in fat and sugar. This would make them more likely to want to keep eating these unhealthy foods. American Journal of Clinical Nutrition 2019; 110:1275-86.  

Take Home Message

This study provides further evidence that there is an addictive component to eating unhealthy foods. I have noticed this with my clients for years. Although the mechanisms are not quite clear, it appears that the more high sugar and high fat food you eat, the more you want.

Egg consumption and dementia

The Study

Moderate egg consumption has been associated with improved cognitive function in the research literature. This may be due to the high content of phosphatidylcholine in eggs. This study examined the association between phosphatidylcholine and risk of dementia in 2,497 middle-aged men from Finland. After 21 years of follow-up, men who consumed the most phosphatidylcholine had a 28% lower risk of dementia when compared to men who consumed the least. Even more impressive was that in a subset of the study, men who consumed the most phosphatidylcholine performed significantly better in tests of memory and verbal fluency. American Journal of Clinical Nutrition 2019;110:1416-1423.

Take Home Message

This is a very interesting study. For years, eggs were vilified because of their high cholesterol content. While you don’t want to go overboard with eggs, I tell my clients that up to 6 yolks a week are fine. Eggs yolks contain a lot of healthy nutrients. This study adds to that list of healthy nutrients. Just one note- if you have diabetes, it is a good idea to limit egg yolk consumption. Some research has shown an increased risk of heart disease in diabetics who consumed a lot of egg yolks.

Is intermittent fasting the best way to eat for our weight and health?

Intermittent fasting has been the subject of a lot of research and intense conversation of late. A recent review article in The New England Journal of Medicine adds fuel to the debate. What are the pro’s and con’s of intermittent fasting? Is it the easiest way to lose weight? Is it the best strategy for health and longevity? I don’t know if we totally have the answers to these questions just yet, but some conclusions can be drawn from the data we have so far.

The Article 

The article was published in late December in The New England Journal of Medicine by two researchers from John’s Hopkins University School of Medicine (Reference 1). The main thrust of the article is to present the health benefits of intermittent fasting. The authors argue that fasting turns on adaptive cellular responses that improve glucose regulation, increases stress resistance and suppresses inflammation. 

The article discusses the three most studied fasting protocols:

-Alternate day fasting.

-5:2 intermittent fasting, where you fast for 2 days each week.

-Daily time restricted feeding.

The article goes on to describe research that found benefits of intermittent fasting on aging and a wide variety of disease processes, including: cognitive function, obesity, diabetes, cardiovascular disease and cancer.

Conclusions And Recommendations

1) This article presents some very interesting research concerning the health effects of intermittent fasting. This is a well written and well researched article published in the top medical journal in the world. The researchers make some compelling arguments about how fasting can improve health. I think the research in this area is in a really early stage and we need to do a lot more before we have any definitive answers.

2) Having said that, most of the research has been on animals. This can be a problem because animals have a very different physiology compared to humans and many times animal research does not translate to humans much at all. The authors mention this in the conclusion: “Animal models show that intermittent fasting improves health throughout the life span, whereas clinical studies have mainly involved relatively short-term interventions, over a period of months. It remains to be determined whether people can maintain intermittent fasting for years and potentially accrue the benefits seen in animal models” (Reference 1).

3) When it comes to weight loss strategies, I am not at all convinced that intermittent fasting is the way to go. I feel this way for several reasons:

-In most of the studies that I have seen, there is no greater weight loss when comparing fasting and a more standard continuous calories restriction. I researched two of the weight loss studies cited in this review (References 2 and 3). These studies compared continuous calorie restriction to intermittent fasting. In both of these investigations, the amount of weight loss was the same whether fasting was used or continuous calorie restriction was used as a method of weight loss. 

-While there were some benefits to those who fasted, including improved fasting insulin and insulin resistance, there were some negatives as well. Several other research investigations that I have covered in my blog showed negative outcomes with diets using intermittent fasting. These include: an increased LDL cholesterol, glucose dysregulation, increased inflammation, increased hunger, a decreased physical activity level and a decreased energy expenditure. If you want to reference these studies, please refer to this older blog post (click here).

-There can be some real side effects to intermittent fasting. This was apparent in both of the weight loss studies that I downloaded from the review. In the British Journal of Nutrition article, subjects in the intermittent fasting group were more likely to report constipation, headache, feeling light-headed and being preoccupied with food as side effects (Reference 2). Furthermore, the subjects fasting were more likely to have deficiencies in important nutrients such as magnesium, zinc, selenium and fiber.
In the International Journal of Obesity article, subjects fasting were more likely to report negative side effects such as lack of energy, headache, constipation, lack of concentration and hunger (Reference 3).

-Another major issue for me is the nutritional composition of the diet. If you are seriously restricting your food intake several days each week, there is no way that you will be getting enough vitamins, minerals, fiber, antioxidants, fruits, vegetables, etc. Supplementing with vitamins is just not the same.

In conclusion, this article on fasting in The New England Journal of Medicine is very interesting.  There appears to be some real health benefits for animals. It remains to be seen if these benefits translate to humans over the long term. As a weight loss strategy, it is my opinion that fasting is not the easiest or most effective strategy.

References

1) de Cabo R, et al. Effects of intermittent fasting on health, aging and disease. New England Journal of Medicine 2019; 381:2541-51.

2) Harvie M, et al. The effect of intermittent energy and carbohydrate restriction v daily energy restriction on weight loss and metabolic disease risk markers in overweight women. British Journal of Nutrition 2013; 110:1534-47.

3) Harvie M, et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. International Journal of Obesity 2011; 35:714-27.