Белок, связывающий жирные кислоты (H-FABP)

Fatty acids analysis (saturated and monounsaturated) quantifies major saturated and monounsaturated fatty acids to characterize their balance in vivo. Results support evaluation of dyslipidemias and ischemic heart disease and may be used adjunctively in the assessment, prognostic evaluation, and treatment planning of selected malignancies, including colorectal, pancreatic, prostate, and breast cancer. The test is also referred to as a saturated and monounsaturated fatty acids profile.

Fatty acids are long-chain carboxylic acids that provide metabolic fuel, form cellular membranes, transport fat-soluble vitamins, and serve as precursors of mediators involved in transcription and intracellular signaling. They are classified by the number of double bonds: saturated (none), monounsaturated (one), and polyunsaturated (multiple). Predominant saturated species encountered in human samples include acetic, propionic, butyric, valeric, caproic, lauric, myristic, palmitic, and stearic acids, while key monounsaturated species include myristoleic, palmitoleic, and oleic acids. Measuring these constituents allows evaluation of their distribution and balance in circulation. Dietary sources differ markedly in fatty acid composition. Butter contains approximately 51% saturated fatty acids, 21% monounsaturated fatty acids, and 3% polyunsaturated fatty acids, whereas olive oil is enriched in monounsaturated fatty acids (about 73%) with lower proportions of saturated (14%) and polyunsaturated (10.5%) fatty acids. Saturated fatty acids are broadly associated with adverse lipid effects and higher ischemic heart disease risk—particularly palmitic, lauric, and myristic acids, which are linked to increased very-low-density lipoprotein cholesterol—although lauric and myristic acids also raise high-density lipoprotein cholesterol. Excess intake of saturated fatty acids has been associated with increased risk of gastrointestinal, breast, and prostate malignancies. Accordingly, recommended saturated fat intake does not exceed 10–15% of daily calories, with a stricter target of less than 7% for individuals with ischemic heart disease, diabetes, or dyslipidemia. Not all saturated fatty acids act uniformly: caproic acid shows no effect on circulating cholesterol, and stearic acid may modestly lower cholesterol by reducing intestinal reabsorption. Some saturated fatty acids demonstrate protective properties; caproic acid exhibits antiviral activity, including activity against HIV, and lauric acid has antibacterial effects (including activity against Helicobacter pylori) and contributes to prevention of dental caries and plaque formation. Higher intake of monounsaturated fatty acids is associated with increased HDL cholesterol, lower triglycerides, reductions in systolic and diastolic blood pressure among individuals with hypertension, and decreased glucose and glycated hemoglobin in diabetes. Replacing saturated fatty acids with monounsaturated fatty acids is recommended, with an optimal monounsaturated fat intake of 15–25% of total calories. Absorption and metabolism of fatty acids vary with sex, age, habitual diet, physical activity, and comorbid conditions; interpretation of the saturated and monounsaturated fatty acids profile should be integrated with clinical history and other laboratory data.