T his document presents guidelines for reducing the risk of cardiovascular disease by dietary and other lifestyle practices. Since the previous publication of these guidelines by the American Heart Association, 1 the overall approach has been modified to emphasize their relation to specific goals that the AHA considers of greatest importance for lowering the risk of heart disease and stroke. The revised guidelines place increased emphasis on foods and an overall eating pattern and the need for all Americans to achieve and maintain a healthy body weight (Table).The major guidelines are designed for the general population and collectively replace the "Step 1" designation used for earlier AHA population-wide dietary recommendations. More individualized approaches involving medical nutrition therapy for specific subgroups (for example, those with lipid disorders, diabetes, and preexisting cardiovascular disease) replace the previous "Step 2" diet for higher-risk individuals.The major emphasis for weight management should be on avoidance of excess total energy intake and a regular pattern of physical activity. Fat intake of Յ30% of total energy is recommended to assist in limiting consumption of total energy as well as saturated fat. The guidelines continue to advocate a population-wide limitation of dietary saturated fat to Ͻ10% of energy and cholesterol to Ͻ300 mg/d. Specific intakes for individuals should be based on cholesterol and lipoprotein levels and the presence of existing heart disease, diabetes, and other risk factors. Because of increased evidence for the cardiovascular benefits of fish (particularly fatty fish), consumption of at least 2 fish servings per week is now recommended. Finally, recent studies support a major benefit on blood pressure of consuming vegetables, fruits, and low-fat dairy products, as well as limiting salt intake (Ͻ6 grams per day) and alcohol (no more than 2 drinks per day for men and 1 for women) and maintaining a healthy body weight. Overview and SummaryThe AHA has a long-standing commitment to the promotion of lifestyle practices aimed at preventing the development or recurrence of heart and blood vessel diseases and promoting overall well-being. An important component of this mission has been the provision of dietary guidelines for the American population that are based on the best available scientific evidence. The present statement formulates the core elements of population-wide recommendations for cardiovascular disease prevention and treatment that are supported by decades of research. This revised statement also provides a summary of a number of important ancillary issues, including those for which the scientific evidence is deemed insufficient to make specific recommendations.Three principles underlie the current guidelines:• There are dietary and other lifestyle practices that all individuals can safely follow throughout the life span as a foundation for achieving and maintaining cardiovascular and overall health.• Healthy dietary practices are based on one's overall p...

The current daily recommended dietary allowance for vitamin K is 1 microg/kg. Reliable measurements of vitamin K content in foods are now available, and data from 11 studies of vitamin K intake indicate that the mean intake of young adults is approximately 80 microg phylloquinone/d and that older adults consume approximately 150 microg/d. The vitamin K concentration in most foods is very low (<10 microg/100 g), and the majority of the vitamin is obtained from a few leafy green vegetables and four vegetable oils (soybean, cottonseed, canola and olive) that contain high amounts. Limited data indicate that absorption of phylloquinone from a food matrix is poor. Hydrogenated oils also contain appreciable amounts of 2', 3'-dihydrophylloquinone of unknown physiological importance. Menaquinones absorbed from the diet or the gut appear to provide only a minor portion of the human daily requirement. Measures of the extent to which plasma prothrombin or serum osteocalcin lack essential gamma-carboxyglutamic acid residues formed by vitamin K action, or the urinary excretion of this amino acid, provide more sensitive measures of vitamin K status than measures of plasma phylloquinone or insensitive clotting assays.

T his document presents guidelines for reducing the risk of cardiovascular disease by dietary and other lifestyle practices. Since the previous publication of these guidelines by the American Heart Association, 1 the overall approach has been modified to emphasize their relation to specific goals that the AHA considers of greatest importance for lowering the risk of heart disease and stroke. The revised guidelines place increased emphasis on foods and an overall eating pattern and the need for all Americans to achieve and maintain a healthy body weight (Table).The major guidelines are designed for the general population and collectively replace the "Step 1" designation used for earlier AHA population-wide dietary recommendations. More individualized approaches involving medical nutrition therapy for specific subgroups (for example, those with lipid disorders, diabetes, and preexisting cardiovascular disease) replace the previous "Step 2" diet for higher-risk individuals.The major emphasis for weight management should be on avoidance of excess total energy intake and a regular pattern of physical activity. Fat intake of Յ30% of total energy is recommended to assist in limiting consumption of total energy as well as saturated fat. The guidelines continue to advocate a population-wide limitation of dietary saturated fat to Ͻ10% of energy and cholesterol to Ͻ300 mg/d. Specific intakes for individuals should be based on cholesterol and lipoprotein levels and the presence of existing heart disease, diabetes, and other risk factors. Because of increased evidence for the cardiovascular benefits of fish (particularly fatty fish), consumption of at least 2 fish servings per week is now recommended. Finally, recent studies support a major benefit on blood pressure of consuming vegetables, fruits, and low-fat dairy products, as well as limiting salt intake (Ͻ6 grams per day) and alcohol (no more than 2 drinks per day for men and 1 for women) and maintaining a healthy body weight. Overview and SummaryThe AHA has a long-standing commitment to the promotion of lifestyle practices aimed at preventing the development or recurrence of heart and blood vessel diseases and promoting overall well-being. An important component of this mission has been the provision of dietary guidelines for the American population that are based on the best available scientific evidence. The present statement formulates the core elements of population-wide recommendations for cardiovascular disease prevention and treatment that are supported by decades of research. This revised statement also provides a summary of a number of important ancillary issues, including those for which the scientific evidence is deemed insufficient to make specific recommendations.Three principles underlie the current guidelines:• There are dietary and other lifestyle practices that all individuals can safely follow throughout the life span as a foundation for achieving and maintaining cardiovascular and overall health.• Healthy dietary practices are based on one's overall p...

Vitamin K functions in a microsomal carboxylation reaction that converts glutamyl residues in precursor proteins to -carboxyglutamyl residues in the products of this reaction. The same liver microsomal preparations that carry out this carboxylation also convert the vitamin to its 2,3-epoxide (epoxidase activity) and reduce the epoxide to the vitamin (epoxide reductase activity). The effect of the coumarin anticoagulant Warfarin on these reactions has been studied. The vitamin K dependent carboxylase activity in intact microsomes is dependent on either NADH or dithiothreitol as a source of reducing equivalents to form the biologically active reduced form of the vitamin. The dithiothreitol dependent reaction is inhibited by Warfarin, but the NADH dependent reaction is not. When microsomes are solubilized in detergent, dithiothreitol is no longer an effective source of reducing equivalents, and Warfarin inhibition of the carboxylase activity is lost. The vitamin K epoxide reductase will use dithiothreitol, but not NADH as a reductant, and this reaction is strongly V itamin K functions in the postribosomal modification of liver microsomal protein precursors to form biologically active prothrombin (factor II) and the other vitamin K dependent plasma clotting proteins, factors VII, IX and X (Suttie & Jackson, 1977). This modification involves the carboxylation of specific glutamyl residues in the precursor proteins to form -carboxyglutamyl residues in these proteins (Stenflo & Suttie, 1977), and an in vitro system to study this vitamin K dependent carboxylase has been developed (Esmon et ah, 1975). This reaction has now been studied in microsomal suspensions (

Bacterially produced menaquinones, 2-methyl-1,4-naphthoquinones with an unsaturated polyisoprenoid chain at the 3-position, are biologically active forms of vitamin K that are present in high concentrations in the human lower bowel. Menaquinones are found in human liver and circulate in human plasma at much higher concentrations than previously thought. Numerous case reports of antibiotic-induced, vitamin K-responsive hypothrombinemias have been taken as evidence that menaquinones contribute importantly to satisfying the human vitamin K requirement. However, more recent production of symptoms of vitamin K insufficiency in normal human subjects by dietary restriction of vitamin K argues against their nutritional significance. Current data support the view that menaquinones may partially satisfy the human requirement but that their contribution is much less than previously thought.