Medical Nutrition Therapy for Disorders of Lipid Metabolism
Manual of Clinical Nutrition Management C- 44 Copyright © 2 013 Compass Group, Inc.
of saturated and trans fat per tablespoon and with liquid oil as the first ingredient is recommended in place of
stick margarine. According to the 2005 Academy guidelines, a diet consisting of <7% saturated and trans fat
combined should be the therapeutic goal for saturated and trans fat intake (Grade I) (5). According to the 2006
guidelines from the AHA, a diet should consist of <7% saturated fat and <1% trans fat (3).
Cholesterol: Dietary cholesterol is found only in animal products, especially those foods that are high in
saturated fatty acids (eg, meats and whole dairy products). There is some evidence that dietary cholesterol
enhances the serum cholesterol-raising action of saturated fatty acids, although to a lesser extent than
saturated fat (1,3). Most foods high in saturated fat are also sources of dietary cholesterol. Reduced intake of
foods high in saturated fat provides the additional benefit of limiting cholesterol intake. Cholesterol-rich foods
that are relatively low in saturated fatty acids, notably eggs and, to a lesser extent, shellfish, have smaller effects
on LDL cholesterol (3). Therefore, periodic consumption of eggs and shellfish can be integrated into the
Therapeutic Lifestyle Changes Diet meal plan.
Carbohydrates: Complex carbohydrates should make up the majority of digestible carbohydrates. When fat
intake is reduced and nutrient replacement is required to maintain energy balance, the replacement should be
complex carbohydrates. Recommended sources include whole grains, legumes, fruits, vegetables, nuts, and
low-fat dairy products. Data on the ideal isocaloric substitution of carbohydrate for fat to maximize LDL-
cholesterol lowering are presently not available (Grade V) (5).
Total protein and soy protein: Approximately 15% of total energy should be provided as protein. Currently
there is no scientific evidence to support the concepts that high-protein diets result in sustained weight loss,
significant changes in metabolism, or improved health (7,18). Recent randomized, controlled trials have
demonstrated that consumption of 20 to 50 g of soy protein daily may reduce LDL cholesterol levels (5,19-22).
Studies vary greatly in their estimation of the effect of diets low in saturated fat and cholesterol containing 26 to
50 g of soy protein, either as food or as a soy supplement with 0 to 165 mg of isoflavones (Grade II), and effects
may vary based on initial cholesterol level (Grade III) (5). If consistent with patient preference and not
contraindicated by risks or harms, then soy (eg, isolated soy protein, textured soy, tofu) may be included as part
of a cardioprotective diet. Consuming 26 to 50 g/day of soy protein in place of animal protein can reduce total
cholesterol by 0% to 20% and LDL cholesterol by 4% to 25% (Grade II) (5). Evidence is insufficient to establish a
beneficial role for isoflavones as an independent component (Grade III) (5). Soy protein concentrates that remove
isoflavones during processing may not be as effective (21). In October 1999, the Food and Drug Administration
approved a health claim that allows food label claims for reduced risk of heart disease on foods that contain
more than 6.25 g of soy protein per serving (3). The claim states that 25 g of soy protein per day, as part of a diet
low in saturated fat and cholesterol, may reduce the risk of heart disease. Sources of soy protein include soy
milk, soybeans, tofu, soy-based meat and cheese substitutes, and alfalfa sprouts. Soy protein may not be
recommended in some individuals with breast cancer. Individuals with breast cancer or at high risk for breast
cancer should speak with their physician (5). Consumption of greater than 50 g of soy protein with isoflavones
may cause gastrointestinal distress in some individuals (5). Additionally, care should be taken when introducing
soy into a patient’s diet, because some individuals have an undiagnosed allergy to soy protein (5).
Total energy: Maintaining a balance between energy intake and expenditure is a goal of MNT. Some patients
with high LDL cholesterol levels are sensitive to energy intake. Weight reduction and attainment of a
reasonable body weight will completely correct their elevated LDL cholesterol concentrations. In many people,
weight reduction will also reduce plasma triglycerides levels and raise HDL cholesterol levels (3).
Fiber: An intake of total dietary fiber 25 to 30 g is recommended for adults and is associated with decreased
risk for CHD and cardiovascular disease (Grade II) (3,5,23). Increased intake of foods rich in soluble fiber correlates
with decreased serum cholesterol levels (Grade I) (3,5,23). Consuming diet from whole food or supplements in total
fiber (17 to 30 g/day) and soluble fiber (7 to 13 g/day) as part of a diet low in saturated fat and cholesterol can
further reduce total cholesterol levels by 2% to 3% and LDL cholesterol levels by up to 7% (Grade I) (5). Choosing
soluble fibers (notably beta glucan and pectin) found in oats, barley, and pectin-containing fruits and vegetable,
beans and legumes provides adjunctive lipid-lowering benefits beyond those achieved through the reduction of
total and saturated fat alone (3,23). The AHA recommends the intake of more than 25 g/day of soluble fiber from
a variety of sources, including grains, vegetables, fruits, legumes, and nuts (3).
Other Dietary Factors Influencing Blood Lipid Levels and Risk Factors
Antioxidants: Oxidative processes are involved in the development and clinical expression of cardiovascular
disease, and dietary antioxidants may contribute to disease resistance (3). Epidemiological data suggest that
intake of foods rich in vitamin E, C, and beta carotene as part of a cardioprotective dietary pattern is associated
with decreased risk for coronary artery disease (Grade III) (5,24-29). Most studies have involved the consumption of