Trending Clinical Topic: Fat Intake

Ryan Syrek


December 03, 2021

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From a study analyzing associated stroke risk to findings on cardiovascular disease (CVD) risk and cognitive function, new information on fat consumption led to this week's top trending clinical topic. Notably, new research presented at the virtual American Heart Association (AHA) 2021 Scientific Sessions found that not only is meat consumption associated with increased stroke risk, but vegetable fats may help reduce that risk (see Infographic below).

Fenglei Wang, PhD, and colleagues investigated how total dietary fat, different types of fat, and fats from different foods were associated with incident stroke. During follow-up, 6189 incident strokes were observed, including 2967 ischemic strokes and 814 hemorrhagic strokes. The researchers found that the highest quintile of vegetable fat intake was associated with a lower total stroke risk compared with the lowest quintile (hazard ratio [HR], 0.88; 95% CI, 0.81-0.96; P < .001). Similarly, the highest intake of polyunsaturated fat was also associated with lower total stroke (HR, 0.88; 95% CI, 0.80-0.96; P = .002). The highest intake of nondairy animal fat was associated with an increased risk for total stroke (HR, 1.16; 95% CI, 1.05-1.29; P < .001).

The risk for stroke was lower by 9% per serving per day for vegetable oil but increased by 8% and 12%, respectively, per serving of total red meat or processed red meat. Red meat included beef, pork, or lamb, as well as processed meats such as bacon, sausage, bologna, hot dogs, and salami. "We would recommend that people reduce consumption of red and processed meat, minimize fatty parts of unprocessed meat if consumed, and replace lard or tallow (beef fat) with nontropical vegetable oils such as olive oil, corn or soybean oils in cooking, to lower their stroke risk," Wang said.

Concerns about fat consumption were echoed in a separate study presented at the European Society of Cardiology Congress 2021. Examining the records of more than 114,000 people enrolled in the UK Biobank who completed dietary assessments, researchers examined CVD development over more than 8 years of follow-up. Although no association was seen between overall saturated fatty acid (SFA) intake and cardiovascular risk, the risk for total CVD increased by 19% for every 5% increase in energy consumption from meat SFA; the risk for ischemic heart disease rose by 21%. In contrast, the risk for ischemic heart disease appeared to be reduced by the consumption of SFA from dairy sources, falling by 11% for every 5% increase in intake. In addition, replacing energy intake from meat with that from other sources appeared to reduce the risk for cardiovascular outcomes.

Results of a study on diet and cognition lend further support for avoiding saturated fat. Research presented at the Consortium of Multiple Sclerosis Centers 2021 annual meeting found that a Paleolithic elimination diet (Wahls diet) and a low-saturated-fat diet (Swank diet) were associated with improved cognition in patients with relapsing-remitting multiple sclerosis. The Swank diet restricts saturated fat to a maximum of 15 g per day while providing 20-50 g (4-10 teaspoons) of unsaturated fat per day, with four servings each of whole grains, fruits, and vegetables. The Wahls diet recommends 6-9 servings of fruits and vegetables per day, in addition to 6-12 oz of meat per day, according to sex. Grains, legumes, eggs, and dairy, with the exception of clarified butter or ghee, are not permitted on this diet. Neither the Swank nor the Wahls diet includes processed foods.

After controlling for smoking, alcohol consumption, age, sex, baseline distance 6-minute walk test, body mass index, serum vitamin D, and years with MS, results at 12 and 24 weeks showed significant improvements from baseline in the key outcomes of fatigue and cognitive function, as measured by the Fatigue Scale for Motor and Cognitive Functions (FSMC). Scores were −5.7 and −9.0, respectively, for the Swank diet group and −9.3 and −14.9 for the Wahls group (P ≤ .001 for all comparisons). In addition, a significant reduction was observed in both groups on the total Perceived Deficits Questionnaire (PDQ) at 12 and 24 weeks (Swank, −7.4 and −6.3, respectively; Wahls, −6.8 and −10.8; P ≤ .001 for all). Similar improvements with both diets were noted in an analysis of the mental and physical scores on FSMC and on the PDQ subscales of attention, retrospective memory, prospective memory, and planning.

These findings come just as the AHA released a new scientific statement on diet and lifestyle recommendations. The many suggestions in the statement, published in Circulation, include an emphasis on using liquid plant oils rather than tropical oils (coconut, palm, and palm kernel), animal fats (butter and lard), and partially hydrogenated fats. Saturated and trans fats (animal and dairy fats, and partially hydrogenated fat) should be replaced with nontropical liquid plant oils. From cardiovascular and cognition concerns to stroke risk, findings from around the globe add support to the AHA recommendations and resulted in this week's top trending clinical topic.

Learn more about stroke prevention.


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