Table 2.

Evidence From Human Studies Using Different Research Paradigms for Effects of Selected Foods, Nutrients, and Dietary Patterns on Cardiovascular Diseases

	Ecologic Studies of Clinical End Points*	Randomized Trials of Risk Factors†	Prospective Cohort Studies of Clinical End Points*	Randomized Trials of Clinical End Points*
Foods and beverages
Fruits	++++ ↓	++ ↓	++++ ↓	—
Vegetables	++++ ↓	++ ↓	++ ↓	—
Whole grains	—	+ ↓	++++ ↓	—
Fish	++++ ↓	++ ↓	++++ ↓	+ ↓
Nuts	—	++ ↓	++++ ↓	—
Processed meats	+++ ↑	—	++++ ↑	—
Unprocessed red meats	+++ ↑	—	++ ↔	—
Dairy	++ ↑	+ ↓	+++ ↓	—
Sugar-sweetened beverages	++ ↑	+ ↑	++ ↑	—
Alcohol	+++ ↓	+++ ↓	++++ ↓	—
Nutrients‡
Sodium	++++ ↑	++++ ↑	++ ↑	+ ↑
Dietary fiber	++++ ↓	++++ ↓	++++ ↓	+ ↔
Refined carbohydrates and starches	—	++ ↑	++++ ↑	—
Total fat	+++ ↑	++ ↔	+++ ↔	+++ ↔
Trans fat	+++ ↑	++++ ↑	++++ ↑	—
Polyunsaturated fat in place of:
Saturated fat	+++ ↓	+++ ↓	++++ ↓	+++ ↓
Carbohydrate	++ ↓	+++ ↓	++ ↓	—
Monounsaturated fat in place of:
Saturated fat	++ ↓	+++ ↓	+ ↔ ↓	—
Carbohydrate	++ ↓	+++ ↓	+ ↓	—
Saturated fat in place of:
Carbohydrate∥	+++ ↑	++++ ↑↔§	++++ ↔	+ ↔
Seafood omega-3 fatty acids	+++ ↓	++++ ↓	++++ ↓ †	++ ↓
Plant omega-3 fatty acids	++ ↓	++ ↓	++ ↓ †	+ ↔
Dietary cholesterol	+++ ↑	++++ ↑	+ ↑	—
Dietary patterns
DASH	—	++++ ↓	++++ ↓	+ ↓
Mediterranean	++++ ↓	++++ ↓	++++ ↓	—
Vegetarian	+ ↓	+ ↓	++ ↓	—
Japanese	++++ ↓	—	++ ↓	—

Dashes (—) indicate too few studies performed to provide meaningful evidence; +, conflicting or limited supporting evidence; ++, some evidence from a relatively limited number of studies, but with relevant shortcomings (eg, insufficient numbers of studies, limited types of populations, inadequate sample sizes, or insufficient follow-up) or relevant evidence to the contrary that raises important questions; +++, fairly consistent evidence from several well-conducted studies, but with some perceived shortcomings in the available evidence or some evidence to the contrary that precludes a more definite judgment; ++++, consistent evidence from multiple well-conducted studies, with little or no evidence to the contrary; ↓, evidence for benefit (lower risk) from higher intake; ↑, evidence for harm (increased risk) from higher intake; ↔, evidence for no appreciable effects (null); and DASH, Dietary Approaches to Stop Hypertension.

^*Based on the strongest evidence for effects on any single major clinical end point, including coronary heart disease, stroke, or diabetes.

^†Based on the strongest evidence for effects on any single major risk factor, including blood pressure, blood lipids, plasma glucose or insulin resistance, heart rate, or systemic inflammation.

^‡See text and Table 4 for evidence on minerals, vitamins, and other supplements.

^§Lowering of low-density lipoprotein cholesterol, but also lowering of high-density lipoprotein cholesterol and no change in the ratio of total cholesterol to high-density lipoprotein cholesterol.

^∥The evidence for effects of consuming saturated fat in place of polyunsaturated fat or monounsaturated fat is summarized above for the reverse exchanges, ie, polyunsaturated fat in place of saturated fat, and monounsaturated fat in place of saturated fat.