Brush Up on the Downsides of Beef

Several recent studies and reports have described the health challenges that red meat consumption poses, especially the potential role of trimethylamine N-oxide (TMAO) in increasing cardiovascular disease. Take this brief test to find out what you know about the latest findings.

1. According to a dietary intervention study, what effect did chronic ingestion of red meat have on plasma and urine TMAO levels?

A. Slight decrease
B. 2-fold increase
C. 4-fold increase
D. No effect

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Answer: B. 2-fold increase. TMAO increased 2-fold with ingestion of red meat, but not white meat or non-meat in the dietary intervention study published February 14 in European Heart Journal. Researchers also found that red meat significantly reduced fractional renal excretion of TMAO; discontinuation of dietary red meat reduced plasma TMAO within 4 weeks; and dietary-saturated fat did not affect TMAO.

2. In 2 prospective cohort studies in the US, an increase in red meat consumption over 8 years was directly associated with risk of death during the subsequent:

A. Year
B. 2 years
C. 8 years
D. 16 years

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Answer: C. 8 years. According to the recent studies published June 12 in The BMJ, an increase in red meat intake over 8 years was directly linked with risk of mortality during the following 8 years. This rise in death risk was independent of initial red meat intake and concurrent changes in lifestyle factors and was greater with processed vs unprocessed meat. A decrease in total red meat consumption and an increase in alternative protein sources as well as eating healthy, plant-based foods resulted in improved longevity.

3. Researchers recently concluded that more favorable changes in blood lipids and lipoproteins may be achieved by substituting red meat with which comparison diet?

A. Poultry
B. High-quality plant protein
C. Fish
D. Carbohydrates

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Answer: B. High-quality plant protein. In an updated meta-analysis published April 8 in Circulation, authors concluded that more favorable changes in blood lipids and lipoproteins can be achieved by substituting red meat with high-quality plant protein vs fish or low-quality carbohydrates. Red meat intake also resulted in lesser decreases in triglycerides vs all comparison diets combined; lesser decreases in total cholesterol and low-density lipoprotein (LDL) vs high-quality plant protein sources; greater decreases in LDL and high-density lipoprotein vs fish; and greater decreases in triglycerides vs carbohydrates.

4. In a new study, levels of LDL cholesterol (LDL-C), apolipoprotein B (apoB), small and medium LDL particles, and total/HDL cholesterol differed significantly with red vs white meat consumption.

A. True
B. False

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Answer: B. False. These primary outcomes did not differ significantly with consumption of red or white meat according to results of a randomized controlled study published July 1 in The American Journal of Clinical Nutrition. LDL-C and apoB levels were higher with red or white meat vs nonmeat independent of saturated fatty acid (SFA) content. However, high SFA increased LDL-C, apoB, and large LDL particles independent of protein source. Researchers did not find evidence for choosing white meat over red meat for reducing cardiovascular risk.

5. Which of the following describes the trends in protein consumption among US adults over the past 18 years?

A. Processed meat, unchanged; unprocessed red meat, down; poultry, up; fish/shellfish, unchanged
B. Processed meat, down; unprocessed red meat, up; poultry, up; fish/shellfish, up
C. Processed meat, up; unprocessed red meat, down; poultry, unchanged; fish/shellfish, up
D. Processed meat, down; unprocessed red meat, up; poultry, down; fish/shellfish, unchanged

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Answer: A. Processed meat, unchanged; unprocessed red meat, down; poultry, up; fish/shellfish, unchanged. A new analysis, published in the July issue of the Journal of the Academy of Nutrition and Dietetics, found that processed meat consumption in the US has not declined in spite of growing health concerns. The analysis also found that unprocessed red meat intake declined (mean change of -56.7 g/week); poultry increased (mean change of 47 g/week); and fish/shellfish stayed the same (mean change of 1.55 g/week).

For more information on all questions and answers, please visit Red Meat Poses New Challenges.