Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.
Am J Clin Nutr. 2019 Aug 1;110(2):305-315. doi: 10.1093/ajcn/nqz095.
Direct comparisons between SFAs varying in chain length, specifically palmitic acid (16:0) and stearic acid (18:0), relative to the latter's metabolic product, oleic acid (18:1), on cardiometabolic risk factors are limited.
The aim of this study was to determine the relative comparability of diets enriched in palmitic acid, stearic acid, and oleic acid on inflammation and coagulation markers, T lymphocyte proliferation/ex-vivo cytokine secretion, plasma cardiometabolic risk factors, and fecal bile acid concentrations.
Hypercholesterolemic postmenopausal women (n = 20, mean ± SD age 64 ± 7 y, BMI 26.4 ± 3.4 kg/m2, LDL cholesterol ≥ 2.8 mmol/L) were provided with each of 3 diets [55% energy (%E) carbohydrate, 15%E protein, 30%E fat, with ∼50% fat contributed by palmitic acid, stearic acid, or oleic acid in each diet; 5 wk/diet phase] using a randomized crossover design with 2-wk washouts between phases. Outcome measures were assessed at the end of each phase.
Fasting LDL-cholesterol and non-HDL-cholesterol concentrations were lower after the stearic acid and oleic acid diets than the palmitic acid diet (all P < 0.01). Fasting HDL-cholesterol concentrations were lower after the stearic acid diet than the palmitic acid and oleic acid diets (P < 0.01). The stearic acid diet resulted in lower lithocholic acid (P = 0.01) and total secondary bile acid (SBA) concentrations (P = 0.04) than the oleic acid diet. All other outcome measures were similar between diets. Lithocholic acid concentrations were positively correlated with fasting LDL-cholesterol concentrations (r = 0.33; P = 0.011). Total SBA, lithocholic acid, and deoxycholic acid concentrations were negatively correlated with fasting HDL cholesterol (r = -0.51 to -0.44; P < 0.01) concentrations and positively correlated with LDL cholesterol:HDL cholesterol (r = 0.37-0.54; P < 0.01) ratios.
Dietary stearic acid and oleic acid had similar effects on fasting LDL-cholesterol and non-HDL-cholesterol concentrations and more favorable ones than palmitic acid. Unlike oleic acid, the hypocholesterolemic effect of stearic acid may be mediated by inhibition of intestinal hydrophobic SBA synthesis. These findings add to the data suggesting there should be a reassessment of current SFA dietary guidance and Nutrient Facts panel labeling.This trial was registered at clinicaltrials.gov as NCT02145936.
关于长链饱和脂肪酸（棕榈酸，16：0）和硬脂酸（18：0）与它们的代谢产物油酸（18：1）之间对心血管代谢风险因素的影响的直接比较研究有限。
本研究旨在确定富含棕榈酸、硬脂酸和油酸的饮食在炎症和凝血标志物、T 淋巴细胞增殖/体外细胞因子分泌、血浆心血管代谢风险因素和粪便胆汁酸浓度方面的相对可比性。
采用随机交叉设计，每个阶段 5 周饮食，2 周洗脱期，用 3 种饮食（碳水化合物占 55%能量[E]，蛋白质占 15%E，脂肪占 30%E，每种饮食中约 50%的脂肪由棕榈酸、硬脂酸或油酸提供）为 20 名高胆固醇血症绝经后妇女（平均年龄 64±7 岁，BMI 26.4±3.4 kg/m2，LDL 胆固醇≥2.8 mmol/L）提供。在每个阶段结束时评估结局指标。
与棕榈酸饮食相比，硬脂酸和油酸饮食后空腹 LDL-胆固醇和非高密度脂蛋白胆固醇浓度较低（均 P<0.01）。与棕榈酸和油酸饮食相比，空腹 HDL-胆固醇浓度在硬脂酸饮食后较低（P<0.01）。与油酸饮食相比，硬脂酸饮食导致胆酸（P=0.01）和总次级胆汁酸（SBA）浓度较低（P=0.04）。饮食之间所有其他结局指标相似。胆酸浓度与空腹 LDL-胆固醇浓度呈正相关（r=0.33；P=0.011）。总 SBA、胆酸和脱氧胆酸浓度与空腹 HDL 胆固醇浓度呈负相关（r=-0.51 至-0.44；P<0.01），与 LDL 胆固醇：HDL 胆固醇比值呈正相关（r=0.37-0.54；P<0.01）。
膳食硬脂酸和油酸对空腹 LDL-胆固醇和非高密度脂蛋白胆固醇浓度的影响与棕榈酸相似，且比棕榈酸更有利。与油酸不同，硬脂酸的降胆固醇作用可能是通过抑制肠道疏水性 SBA 合成介导的。这些发现增加了数据表明，应该重新评估当前的 SFA 饮食指导和营养成分标签。本试验在 clinicaltrials.gov 上注册为 NCT02145936。
