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Cholesterol Lowering Diet Foods Reduce LDL-Cholesterol by 14%
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"Overall adherence with the 4 principal portfolio components (nuts, soy, viscous fiber, and plant sterol) was significantly associated with the percentage reduction in LDL-C in participants who completed the study (r = -0.34, n = 157, P < .001)."
"The LDL-C reductions from an overall mean of 171 mg/dL were -13.8% or -26 mg/dL for the intensive dietary portfolio (counselling + diet) ; or -24 mg/dL for the routine dietary portfolio; and -3.0% or -8 mg/dL for the control diet."
"The goal of the dietary portfolio was to provide 0.94 g of plant sterols per 1000 kcal of diet in a plant sterol ester-enriched margarine; 9.8 g of viscous fibers per 1000 kcal of diet from oats, barley, and psyllium; 22.5 g of soy protein per 1000 kcal as soy milk, tofu, and soy meat analogues; and 22.5 g of nuts (including tree nuts and peanuts) per 1000 kcal of diet. Consumption of peas, beans, and lentils was also encouraged. This dietary portfolio has been described in detail previously."
"Objective To assess the effect of a dietary portfolio administered at 2 levels of intensity on percentage change in low-density lipoprotein cholesterol (LDL-C) among participants following self-selected diets......Intervention Participants received dietary advice for 6 months on either a low- saturated fat therapeutic diet (control) or a dietary portfolio, for which counseling was delivered at different frequencies, that emphasized dietary incorporation of plant sterols, soy protein, viscous fibers, and nuts. Routine dietary portfolio involved 2 clinic visits over 6 months and intensive dietary portfolio involved 7 clinic visits over 6 months.....Main Outcome Measures Percentage change in serum LDL-C.....Main Outcome Measures Percentage change in serum LDL-C."
"Although there are no data on plant sterol consumption and reduction in CHD risk, cohort studies have consistently shown that consumption of 5 servings of nuts a week, similar to the 26 to 31 g/d consumed in our study, is associated with a decrease in CHD events by 40% to 60%. Fiber intake has been negatively associated with CHD risk. Increased consumption of vegetable sources of protein and fat is associated with reductions in CHD risk. Similar associations were identified for soy protein consumption in the Shanghai cohort."
Cholesterol-Lowering Foods Beat Low-Saturated Fat Diet
By Kristina Fiore, Staff Writer, MedPage Today
Published: August 23, 2011
Eating a predominantly vegetarian diet focused on lowering cholesterol -- and getting advice on how to do so effectively -- can drop LDL levels more than a diet focused only on reducing saturated fat, researchers found.
A diet rich in cholesterol-lowering foods dropped LDL by 13% to 14% over six months, depending on the level of accompanying counseling, compared with a drop of just 3% for patients on a control diet, David Jenkins, MD, of St. Michael's Hospital in Toronto, and colleagues reported in the August 24/31 issue of the Journal of the American Medical Association.
"Our data demonstrate the cholesterol-lowering potential of a dietary portfolio intervention that counsels participants to increase consumption of cholesterol-lowering foods denoted by the FDA to have a heart-health benefit," they wrote.
Foods with known cholesterol-lowering properties -- such as nuts, soy, and barley -- have been shown to be effective in lowering serum cholesterol in metabolically controlled conditions, the researchers said.
So they assessed whether eating a diet consisting of these foods decreased LDL cholesterol compared with a control diet that emphasized eating fiber and whole grains.
They enrolled 351 patients with hyperlipidemia at four centers across Canada, who were given one of three diet plans: a "dietary portfolio" that emphasized plant sterols, soy protein, viscous fibers, and nuts with either two counseling sessions or seven sessions over six months, or a control diet focused on lowering saturated fats without counseling. Control patients were not allowed to eat foods in the intervention portfolio, the researchers said.
The 51 patients who were taking statins before the study had discontinued them at least two weeks prior.
Mean LDL cholesterol at baseline was 171 mg/dL.
In the modified intention-to-treat analysis of 345 patients, the researchers saw significant reductions in LDL cholesterol only for patients in both arms of the portfolio diet: a 13.8% reduction for those who had intensive counseling and a 13.1% drop for those with "routine" counseling (P<0.001 for both) compared with a nonsignificant 3% drop for those on the control diet.
Jenkins and colleagues said the LDL reductions were "approximately half those observed with early statin trials, that were associated with 20% reductions in coronary heart disease mortality."
"Further study is needed to determine whether cholesterol reduction using these portfolio components is associated with lower rates of coronary heart disease events," they wrote.
They also noted that more frequent visits to the clinic appear to be unnecessary in achieving significant reductions in LDL. "The near maximal effectiveness of only two clinic visits enhances the suitability of this dietary approach for clinical application," they added.
The portfolio diet also improved the ratio of total cholesterol to HDL cholesterol, dropping 8.2% for the routine counseling and 6.6% for the intensive counseling (P<0.001 for both). Those reductions were significantly greater than those for the control diet, but weren't significantly different from each other, the researchers said.
The cholesterol-lowering diet also reduced the calculated 10-year heart risk by 10.8% for those on routine counseling and by 11.3% for those on intense counseling, which was significantly greater than the nonsignificant 0.5% drop in risk for those on the control diet.
The researchers noted that reductions in LDL were associated with dietary adherence for those on the cholesterol-lowering diet (P<0.001).
"Convincing people to change dietary patterns is difficult, much less convincing them to become vegetarians," Jana Klauer, MD, a primary care physician in New York, said in an email to MedPage Today and ABC News. "But it can be done -- just look at Bill Clinton," noting the former president and heart disease patient who recently became a vegan in order to glean its benefits to lower his cardiovascular risk.
But Merle Myerson, MD, EdD, of St. Luke's and Roosevelt Hospitals in New York, said the counseling component is perhaps the trickiest part.
"Medicare and most insurances do not reimburse for one session of nutrition counseling, unless you have diabetes or end-stage renal disease, much less the kind of patients in this study," she said, adding that she doubts patient adherence would be sufficient in the long run.
The study was limited because the intervention was complex and lipid-lowering effects couldn't be pegged to specific components. Also, they cautioned about its high overall dropout rate of 22.6%, though they noted this is "an attrition rate common to dietary studies at these levels of intensity."
As well, the study may lack generalizability because its population was predominantly white, with low-to-intermediate risk of cardiovascular disease, and may not translate to those with a higher risk of disease.
Still, they concluded that "a meaningful 13% LDL reduction can be obtained after only two clinic visits of approximately 60- and 40-minute sessions."
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Effect of a Dietary Portfolio of Cholesterol-Lowering Foods Given at 2 Levels of Intensity of Dietary Advice on Serum Lipids in Hyperlipidemia - pdf attached
A Randomized Controlled Trial
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Abstract
Context Combining foods with recognized cholesterol-lowering properties (dietary portfolio) has proven highly effective in lowering serum cholesterol under metabolically controlled conditions.
Objective To assess the effect of a dietary portfolio administered at 2 levels of intensity on percentage change in low-density lipoprotein cholesterol (LDL-C) among participants following self-selected diets.
Design, Setting, and Participants A parallel-design study of 351 participants with hyperlipidemia from 4 participating academic centers across Canada (Quebec City, Toronto, Winnipeg, and Vancouver) randomized between June 25, 2007, and February 19, 2009, to 1 of 3 treatments lasting 6 months.
Intervention Participants received dietary advice for 6 months on either a low- saturated fat therapeutic diet (control) or a dietary portfolio, for which counseling was delivered at different frequencies, that emphasized dietary incorporation of plant sterols, soy protein, viscous fibers, and nuts. Routine dietary portfolio involved 2 clinic visits over 6 months and intensive dietary portfolio involved 7 clinic visits over 6 months.
Main Outcome Measures Percentage change in serum LDL-C.
Results In the modified intention-to-treat analysis of 345 participants, the overall attrition rate was not significantly different between treatments (18% for intensive dietary portfolio, 23% for routine dietary portfolio, and 26% for control; Fisher exact test, P = .33). The LDL-C reductions from an overall mean of 171 mg/dL (95% confidence interval [CI], 168-174 mg/dL) were -13.8% (95% CI, -17.2% to -10.3%; P < .001) or -26 mg/dL (95% CI, -31 to -21 mg/dL; P < .001) for the intensive dietary portfolio; -13.1% (95% CI, -16.7% to -9.5%; P < .001) or -24 mg/dL (95% CI, -30 to -19 mg/dL; P < .001) for the routine dietary portfolio; and -3.0% (95% CI, -6.1% to 0.1%; P = .06) or -8 mg/dL (95% CI, -13 to -3 mg/dL; P = .002) for the control diet. Percentage LDL-C reductions for each dietary portfolio were significantly more than the control diet (P < .001, respectively). The 2 dietary portfolio interventions did not differ significantly (P = .66). Among participants randomized to one of the dietary portfolio interventions, percentage reduction in LDL-C on the dietary portfolio was associated with dietary adherence (r = -0.34, n = 157, P < .001).
Conclusion Use of a dietary portfolio compared with the low-saturated fat dietary advice resulted in greater LDL-C lowering during 6 months of follow-up.
Diets
Table 1 shows diets for participants in each study group before enrollment. During the 6-month study period, dietitians counseled participants to follow weight-maintaining vegetarian diets from foods available in supermarkets and health food stores. Counseling periods were 1-hour duration for the first visit and 30 to 40 minutes at subsequent visits. For participants in the dietary portfolio interventions, dietitians focused on incorporating study foods (eTable 1) into the participants' regular diets using their 7-day food diaries as templates. Participants were provided with a 7-day study food checklist and an illustrated study booklet. The goal of the dietary portfolio was to provide 0.94 g of plant sterols per 1000 kcal of diet in a plant sterol ester-enriched margarine; 9.8 g of viscous fibers per 1000 kcal of diet from oats, barley, and psyllium; 22.5 g of soy protein per 1000 kcal as soy milk, tofu, and soy meat analogues; and 22.5 g of nuts (including tree nuts and peanuts) per 1000 kcal of diet. Consumption of peas, beans, and lentils was also encouraged. This dietary portfolio has been described in detail previously.10
Agencies concerned with cardiovascular health have uniformly stressed the importance of diet and lifestyle as the primary means of lowering serum lipids and coronary heart disease (CHD) risk.1 ,2,3 Nevertheless, the introduction of statins in the late 1980s highlighted the relative ineffectiveness of conventional dietary advice.4 As a result, alternative dietary paradigms have been proposed5 ,6,7 and efforts have been made to enhance the ability of conventional dietary therapy to reduce serum cholesterol through the inclusion of specific foods or food components with known cholesterol-lowering properties,1,8 singly or in combination (dietary portfolio).9 Use of these cholesterol-lowering dietary components in combination in short-term studies with all food provided has been shown to reduce serum low-density lipoprotein cholesterol (LDL-C) to a similar extent as first-generation statins.10 ,11 The longer-term effect of such diets compared with conventional dietary advice has not been assessed.
The control dietary advice focused on low-fat dairy and whole grain cereals together with fruit and vegetables and avoidance of the specific portfolio components. Participants were provided with measuring cups and measuring spoons to assist in portion control.
INTRODUCTION
We therefore undertook a multicenter trial to determine whether advice to eat a dietary portfolio consisting of foods recognized by the US Food and Drug Administration (FDA) as associated with lowering serum cholesterol achieved significantly greater percentage decreases in LDL-C compared with a control diet at 6-month follow-up. The control diet emphasized high fiber and whole grains but lacked portfolio components. To increase the relevance of the study for routine clinical application, the advice was given at 2 levels of intensity, either as a routine dietary portfolio (2 clinic visits of 40- to 60-minute sessions) or an intensive dietary portfolio (7 clinic visits of 40- to 60-minute sessions).
COMMENT
Our data demonstrate the cholesterol-lowering potential of a dietary portfolio intervention that counsels participants to increase consumption of cholesterol-lowering foods denoted by the US FDA to have a heart health benefit and that have also been recommended in national guidelines to enhance the effectiveness of cholesterol-lowering therapeutic diets.1 ,10 Our study also represents the first randomized trial to our knowledge to assess the ability of an intervention that counsels for consumption of these cholesterol-lowering foods to reduce LDL-C at 6-month follow-up in real-world conditions. The reductions in LDL-C in the dietary portfolio intervention were approximately half those observed with early statin trials that were associated with 20% reductions in CHD mortality.17
Although there are no data on plant sterol consumption and reduction in CHD risk, cohort studies have consistently shown that consumption of 5 servings of nuts a week, similar to the 26 to 31 g/d consumed in our study, is associated with a decrease in CHD events by 40% to 60%.18,19 Fiber intake has been negatively associated with CHD risk.20,21 Increased consumption of vegetable sources of protein and fat is associated with reductions in CHD risk.22 Similar associations were identified for soy protein consumption in the Shanghai cohort.23 Further study is needed to determine whether cholesterol reduction using these portfolio components is associated with lower rates of CHD events.
The specific food components used in the portfolio have well-established cholesterol-lowering properties and are recognized by the US FDA as justifying a heart health claim.10 Review articles and meta-analyses have confirmed LDL-C benefits for viscous fibers,24 ,25 plant sterols,26 ,27 soy protein,28 ,29,30 and nuts.31
On the basis of the reported intake of portfolio components, one might expect a 4% LDL-C reduction from viscous fiber, 2% each from nuts and soy, and 5% from plant sterols, resulting in 13% LDL-C reduction. A reduction of a similar magnitude (13%-14%) was observed in our study.
This is the first study to our knowledge to assess the effect of frequency of visit on dropout rate, adherence, and outcome. Although a small reduction was observed in the dropout rate by increasing the frequency of visits from 2 to 7 during the 6-month period, no advantage was observed in terms of dietary adherence or the percentage LDL-C reduction at 24 weeks. More frequent clinic attendance therefore appears to be unnecessary in achieving a significant percentage reduction in LDL-C. The near maximal effectiveness of only 2 clinic visits enhances the suitability of this dietary approach for clinical application.
The study had limitations. First, the intervention was complex. Second, colinearity between the different dietary components did not permit attribution of the lipid-lowering effect to specific components of the intervention. Third, the study was not metabolically controlled in terms of providing all food to the participants. However, our goal was to assess the effect of dietary advice in real-world conditions. Studies of longer duration in which provision of specific diets was possible have relied on workplace or institutional environments.7 ,32,33 ,34 Fourth, the study had a high overall dropout rate of 22.6%. This attrition rate is common to dietary studies provided at these levels of intensity.35 ,36,37 In addition, participants were predominantly white with low to intermediate risk of cardiovascular disease and relatively low mean body mass index levels. The generalizability of this clinical trial to higher-risk, more overweight, or obese patient populations is unknown.
The study advantages include its multicenter nature with centers from across the continent. Participants who joined the study were already consuming an acceptable background diet low in saturated fat and cholesterol to provide a fairer illustration of the type of patients for whom standard dietary advice has failed to achieve therapeutic targets. This approach may underestimate the effectiveness of the diet when applied to those individuals who are not already following therapeutic diets. However, it is also possible that participants in this study are better able to adhere to healthy diets than those who chose not to participate. Many of the foods have other attributes, including lowering the glycemic index, which may aid in reducing disease risk for CHD, diabetes, and obesity.38 In addition, the dietary portfolio treatments lowered LDL-C without also lowering HDL-C.
In conclusion, this study indicated the potential value of using recognized cholesterol-lowering foods in combination. We believe this approach has clinical application. A meaningful 13% LDL-C reduction can be obtained after only 2 clinic visits of approximately 60- and 40-minute sessions. The limited 3% LDL-C reduction observed in the conventional diet is likely to reflect the adequacy of the baseline diet and therefore suggests that larger absolute reductions in LDL-C may be observed when the dietary portfolio is prescribed to patients with diets more reflective of the general population.
RESULTS
The study was conducted between 2007 and 2009, and randomization took place between June 25, 2007, and February 19, 2009. The baseline characteristics of the participants were similar for all 3 treatments, with the exception of the ratio of men to women, which was higher on the intensive portfolio than on the other 2 treatments (Table 2). No participants were taking medications known to influence serum lipids, except 31 women and 4 men who were all receiving stable doses of thyroxine and 12 women who were receiving estrogen therapy. Fifty-one participants (14%) had been taking statins before the study commenced and had discontinued taking the medications at least 2 weeks before the study (Table 2).
The mean overall adherence for all participants to the intensive dietary portfolio was 46.4% (95% CI, 40.4%-52.4%) and to the routine dietary portfolio was 40.6% (95% CI, 34.6%-46.6%). Participants lost a similar amount of weight while taking part in all 3 treatments (intensive dietary portfolio, -1.2 kg; 95% CI, -1.9 to -0.6 kg; P < .001; routine dietary portfolio, -1.7 kg; 95% CI, -2.4 to -1.0 kg; P < .001; and control, -1.5 kg; 95% CI, -2.1 to -0.8 kg; P < .001) (Table 3).
Blood Lipids, Apolipoproteins, and CRP
No differences were observed between the 3 treatment groups in baseline blood measurements. In the modified intention-to-treat analysis, the percentage changes from baseline to week 24 in the control diet were -3.0% (95% CI, -6.1% to 0.1%; P = .06) or -8 mg/dL (95% CI, -13 to -3 mg/dL; P = .002) for LDL-C and -1.4% (95% CI, -4.3% to 1.6%; P = .37) or -0.09 (95% CI, -0.24 to 0.05; P = .18) for TC:HDL-C ratio. In the routine and intensive dietary portfolio interventions, the respective percentage changes were -13.1% (95% CI, -16.7% to -9.5%; P < .001) or -24 mg/dL (95% CI, -30 to -19 mg/dL; P < .001) and -13.8% (95% CI, -17.2% to -10.3%; P < .001) or -26 mg/dL (95% CI, -31 to -21 mg/dL; P < .001) for LDL-C; and -8.2% (95% CI, -11.2% to -5.3%; P < .001) or -0.37 (95% CI, -0.52 to -0.23; P < .001) and -6.6% (95% CI, -9.8% to -3.4%; P < .001) or -0.39 (95% CI, -0.56 to -0.24; P < .001) for TC:HDL-C ratio, respectively (Figure 2). The percentage change and absolute treatment differences between the control and both the dietary portfolio interventions were significant for LDL-C (P < .001) and in absolute units for the TC:HDL-C ratio (P = .004 for intensive dietary portfolio and P = .006 for routine dietary portfolio), with no significant differences between the dietary portfolios (P = .66) (Table 3). The apolipoproteins reflected the lipid and lipoprotein changes (Table 3). No significant differences were observed between treatments in CRP. No treatment differences in response were observed between men and women.
Blood Pressure
The intensive dietary portfolio led to a nonsignificant reduction in systolic blood pressure of 2.6 mm Hg (95% CI, -5.4 to -0.2 mm Hg; P = .07) and a significant reduction in diastolic blood pressure of 2.1 mm Hg (95% CI, -3.7 to -0.4 mm Hg; P = .01) compared with the control diet (Table 3).
Calculated CHD Risk
The routine dietary portfolio reduced the calculated 10-year CHD risk by 10.8% (95% CI, -16.8% to -5.0%; P < .001; absolute risk change, -0.9%; 95% CI, -1.4% to -0.5%), with a comparable reduction in the intensive dietary portfolio of -11.3% (95% CI, -17.1% to -5.4%; P < .001; absolute risk change, -1.2%; 95% CI, -1.5% to -0.8%). These percentage reductions were significantly different (P = .02 and P = .01, respectively) from the nonsignificant decrease in the control diet (-0.5%; 95% CI, -6.0% to 5.0%; P = .87; absolute risk change, -0.3%; 95% CI, -0.7% to 0.1%; P = .12) (Table 3).
Completer Analysis
The mean percentage reductions in LDL-C were significant at -15.0% (95% CI, -18.6% to -11.4%; P < .001) or -27 mg/dL (95% CI, -32 to -22 mg/dL) for routine dietary portfolio and -15.5% (95% CI, -19.0% to -12.0%; P < .001) or -28 mg/dL (95% CI, -32 to -22 mg/dL) for intensive dietary portfolio, but not for the control diet (-2.5%; 95% CI, -6.0% to 1.0%; P = .16; or -9 mg/dL; 95% CI, -14 to -4 mg/dL). Both portfolio treatments were different from the control (P < .001) but were similar to each other.
Factors Associated With the Percentage Reduction in LDL-C
Overall adherence with the 4 principal portfolio components (nuts, soy, viscous fiber, and plant sterol) was significantly associated with the percentage reduction in LDL-C in participants who completed the study (r = -0.34, n = 157, P < .001).
Center Differences
The mean percentage LDL-C response of the 2 portfolio treatments for Vancouver (-19.9%; 95% CI, -25.0% to -14.8%; or -33 mg/dL; 95% CI, -41 to -25 mg/dL) differed significantly from both Toronto (-11.6%; 95% CI, -15.6% to -7.6%; or -23 mg/dL; 95% CI, -30 to -17 mg/dL) and Winnipeg (-11.1%; 95% CI, -16.4% to -5.8%; or -22 mg/dL; 95% CI, -30 to -14 mg/dL) for the difference in percentage reduction between centers (P = .01 and P = .02, respectively), and the difference between Vancouver and Quebec (-12.7%; 95% CI, -18.2% to -7.2%; or -26 mg/dL; 95% CI, -35 to -17 mg/dL) was of borderline significance for the percentage reduction in LDL-C (P = .06). Vancouver (48.3%) differed from Winnipeg (34.0%) in terms of adherence (P = .001).
Adverse Clinical Events
There were no serious adverse events or events that required hospitalization (eTable 2). However, 36 minor events were reported during the study (15 in the intensive dietary portfolio, 12 in the routine dietary portfolio, and 9 in the control diet), with no treatment difference in event number (P = .20). None of the events were directly linked to the study intervention, except for 1 man who had recurrent facial flushing and itching at the back of the neck and was found to have positive skin test for soy in the routine dietary portfolio, and 1 woman with a rash and positive skin test for soy and almonds in the intensive dietary portfolio.
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