Monday, November 13, 2023

Should I Avoid Seafood Because It’s High In Mercury?

Seafood is a very healthy food, but because of industrial pollution, there is a legitimate concern of mercury contamination in the fish we consume. So, just where does seafood fit into a healthy diet?

Benefits of Seafood

Seafood contains a lot of healthy nutrients. It is high in Omega 3 fatty acids and Vitamin D. It is also a great source of protein that is low in saturated fat.

Omega 3 fatty acids from seafood have been shown in the research literature to have a nice impact on arrhythmias, triglycerides, inflammation, blood pressure, heart rate and vascular function. This all translates to a significantly lower risk of cardiovascular for those that regularly consume seafood.

Risk of Mercury Consumption

High levels of mercury can harm nerves in adults and have a negative impact on the development of the nervous system and brains of children. Mercury may also increase risk of cardiovascular disease.

What I Tell My Clients

The benefits of seafood consumption are undeniable, but you don’t want to go overboard and load up on mercury either. The goal is to strike a balance by following 2 guidelines:

1) Stick to 3 servings of seafood per week. 

2) Avoid seafood species with the highest levels of mercury: Swordfish, Shark, King Mackerel, Tilefish, Orange Roughy, Marlin and Albacore-, Bigeye- or Yellow-fin tuna.

If you are pregnant, trying to become pregnant or nursing, talk to your doctor about the amount of seafood that is right for you.

Weight Loss With And Without Exercise

The Study

In this interesting trial, 8 obese, prediabetic subjects lost 10% of their body weight by changing their diet and another 8 obese, prediabetic subjects lost 10% of their body weight by changing their diet and exercising. A variety of metabolic tests were conducted both before and after the intervention.

The group that added exercise to their weight loss program had a two-fold improvement in insulin sensitivity. These subjects also had an increased muscular expression of genes involved in the biogenesis of mitochondria, energy metabolism and angiogenesis (which is the creation of new blood vessels).

Nature Metabolism 2023; 5:1221.

Take Home Message

Losing weight by changing your diet is great. Losing weight by changing your diet and exercising is even better. This study is really relevant given the explosion in the use of Ozempic and Mounjaro weight loss medications. Many are losing weight with these drugs while not really paying attention to their diet and exercise programs. This leaves a lot of health benefits on the table. Exercise is an essential component of any weight loss program and should not be neglected.

Are Weekend Warriors Just As Healthy?

The Study

A long-standing debate in the field of exercise science is whether exercising every day is better for your health than just exercising on the weekend. A recent study from England using the UK Biobank cohort put this to the test.

The study included 89,573 subjects who wore an accelerometer for 7 days. The subjects were split into two groups: those that exercised for 150 minutes spread throughout the week and those that exercised for 150 minutes just on 1 or 2 days of the week. The subjects were then followed for cardiovascular events, which included myocardial infarction, stroke and heart failure.

The statistically significant decrease in risk of cardiovascular events did not differ between groups.

JAMA 2023; 330:247.

Take Home Message

This is a really reassuring result for those of us whose jobs make it difficult to exercise during the work week. Do your best to get your cardio in on a daily basis, but if you cannot, you can make up what you miss on the weekend.  This study provides evidence that you won’t be missing out on any of the health benefits.