Dairy Products for Heart Health

Overseen By Jean Galluccio, BS

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Tufts University

Must not be taking: Antibiotics, Steroids, NSAIDs, others

Disqualifiers: Hypertension, Diabetes, Heart disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 8

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines how different types of milk and yogurt affect gut health and heart disease risk. Participants will consume either full-fat or fat-free milk or yogurt to observe changes in gut microorganisms and heart disease risk factors. The study aims to refine dietary guidance for improved heart health. It is suitable for men and postmenopausal women without a milk allergy or lactose intolerance, and with a BMI between 25 and 35, a common measure of weight relative to height. As an unphased trial, it offers participants the chance to contribute to valuable research that could enhance dietary recommendations for heart health.

Will I have to stop taking my current medications?

The trial requires that you stop using certain medications, including oral antibiotics, steroids, lipid-lowering medications, chronic use of aspirin, NSAIDs, laxatives, anti-diarrheal medication, and regular use of acid-lowering medications. If you are taking any of these, you may need to stop before joining the study.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that both full-fat and fat-free dairy products are generally easy to digest. Studies have found that drinking fat-free milk does not significantly increase the risk of heart disease. A review of multiple studies found that consuming dairy can slightly lower the risk of heart disease and stroke.

For fat-free yogurt, evidence suggests that fermented dairy products, like yogurt, may benefit heart health and help prevent conditions that increase heart disease risk.

Regarding full-fat yogurt, studies indicate it does not harm insulin sensitivity, cholesterol levels, or blood pressure. Some research even links full-fat yogurt to a lower risk of stroke.

As for full-fat milk, while some debate exists, research generally shows it does not harm heart health. Some studies suggest full-fat dairy might not be as risky as once thought.

Overall, these findings suggest that the dairy products under study are likely safe and well-tolerated. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about these treatments because they explore how everyday dairy products might improve heart health. Unlike conventional medications that often target cholesterol levels or blood pressure through synthetic drugs, these beverages use natural ingredients like fat-free and full-fat milk or yogurt. The unique aspect here is the potential for these dairy drinks to provide heart benefits through their natural composition, possibly offering a more accessible and less invasive way to support cardiovascular health. By evaluating both fat-free and full-fat options, researchers aim to understand how different types of dairy fats affect heart health, which could lead to personalized dietary recommendations.

What evidence suggests that this trial's treatments could be effective for heart health?

This trial will compare the effects of different dairy beverages on heart health. Research has shown that various types of milk and yogurt can impact heart health in different ways. Participants will receive either a fat-free milk beverage, a fat-free yogurt beverage, a full-fat yogurt beverage, or a full-fat milk beverage. Studies suggest that fat-free milk generally has a neutral effect, meaning it doesn't significantly alter the risk of heart disease. Fermented dairy products like yogurt may help reduce risk factors for heart problems by improving blood fat levels. Specifically, full-fat yogurt has been found to lower total cholesterol and "bad" LDL cholesterol, both linked to heart disease. In contrast, full-fat milk doesn't seem to harm heart health and might even be associated with a lower risk of stroke. Overall, both full-fat and fat-free dairy products offer potential benefits, with fermented yogurt showing particularly promising effects on heart health. ^{1 2 6 7 8}

Who Is on the Research Team?

Alice H Lichtenstein, D. Sc.

Principal Investigator

Tufts University

Are You a Good Fit for This Trial?

This trial is for men and postmenopausal women over 50 with a BMI between 25-35, who don't smoke, have regular bowel movements, and are not on certain medications. Excluded are those underweight or overweight beyond the set limits, recent smokers or nicotine users, hormone therapy recipients, anemia patients within two years, recent blood donors or antibiotic users.

Inclusion Criteria

I am over 50 years old.

Your body mass index (BMI) is between 25 and 35.

You have regular bowel movements at least every other day.

Exclusion Criteria

I have not taken oral antibiotics in the last 2 weeks.

You have donated blood in the last 2 months.

I have a chronic gastrointestinal condition that could affect the study.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Fat-free milk phase

Participants consume 2 servings per day of fat-free milk for 3 weeks

3 weeks

2 visits (in-person) for measurements and sample collection

Full-fat milk phase

Participants consume 2 servings per day of full-fat milk for 3 weeks

3 weeks

2 visits (in-person) for measurements and sample collection

Fat-free yogurt phase

Participants consume 2 servings per day of fat-free yogurt for 3 weeks

3 weeks

2 visits (in-person) for measurements and sample collection

Full-fat yogurt phase

Participants consume 2 servings per day of full-fat yogurt for 3 weeks

3 weeks

2 visits (in-person) for measurements and sample collection

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Milk or yogurt beverage

Trial Overview

The study tests how full-fat and fat-free milk and yogurt affect gut microbes and heart disease risk factors. Participants will consume these dairy products to see if fat content and fermentation influence cardiovascular health.

How Is the Trial Designed?

Group I: Full-fat yogurt beverage Experimental Treatment 1 Intervention

Beverage made with full-fat yogurt

Group II: Full-fat milk beverage Experimental Treatment 1 Intervention

Beverage made with full-fat milk

Group III: Fat-free yogurt beverage Experimental Treatment 1 Intervention

Beverage made with fat-free yogurt

Group IV: Fat-free milk beverage Experimental Treatment 1 Intervention

Beverage made with fat-free milk

Who Is Running the Clinical Trial?

Tufts University

Lead Sponsor

Trials

271

Recruited

595,000+

Published Research Related to This Trial

In a study involving 18 normolipidemic males, yogurt intake (16 oz/day) for 4 weeks did not affect plasma total, LDL, or HDL cholesterol levels compared to a baseline low-fat, low-cholesterol diet.

Similarly, a non-fermented dairy product (low-fat milk) also showed no impact on cholesterol levels, indicating that yogurt and low-fat milk do not influence plasma lipid profiles in healthy individuals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of yogurt intake on plasma lipid and lipoprotein levels in normolipidemic males. McNamara, DJ., Lowell, AE., Sabb, JE.[2019]

Consumption of fermented dairy products like yogurt and cheese is associated with a lower risk of developing type 2 diabetes and cardiovascular diseases, despite cheese's high saturated fat content.

Current evidence suggests that while fermented dairy may help manage certain cardiometabolic risk factors, more research is needed to clarify its effects on hypertension and metabolic syndrome.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fermented dairy foods rich in probiotics and cardiometabolic risk factors: a narrative review from prospective cohort studies. Companys, J., Pedret, A., Valls, RM., et al.[2021]

In a study involving 90 patients with chronic heart failure, those consuming probiotic yogurt for 10 weeks showed a significant reduction in oxidized low-density lipoprotein (oxLDL) levels compared to those consuming ordinary yogurt, suggesting a potential benefit for heart health.

While both groups experienced a decrease in pentraxin3 (PTX3) levels, the difference was not statistically significant, indicating that probiotic yogurt may specifically improve oxidative status in CHF patients rather than affecting all inflammatory markers.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of probiotic yogurt and ordinary yogurt consumption on serum Pentraxin3, NT-proBNP, oxLDL, and ApoB100 in patients with chronic heart failure: a randomized, triple-blind, controlled trial. [2021]

Higher consumption of dairy products, particularly milk and yogurt, in adolescents is associated with lower body fat and a reduced risk of cardiovascular diseases, as indicated by data from the HELENA study involving adolescents aged 12.5-17.5 years from 8 European cities.

The study suggests that dairy products may play a protective role against cardiovascular risk factors in young populations, but further research is needed to understand the underlying mechanisms of this association.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Consumption of dairy products in youth, does it protect from cardio-metabolic risk? Santaliestra-Pasías, AM., Bel-Serrat, S., Moreno, LA., et al.[2018]

Kefir consumption significantly reduces fasting insulin levels and insulin resistance (HOMA-IR), indicating potential benefits for managing blood sugar levels and metabolic health, based on a meta-analysis of six randomized controlled trials involving 314 subjects.

However, kefir did not show any significant effects on body weight, fasting blood sugar, hemoglobin A1c, or lipid profiles, suggesting that while it may help with insulin sensitivity, it does not impact other cardiometabolic risk factors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of Kefir Consumption on Cardiometabolic Risk Factors: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Yahyapoor, F., Haghighat, N., Sohrabi, Z., et al.[2023]

Yogurt, which has been consumed for thousands of years, is made from fermented milk using beneficial bacteria like Lactobacillus bulgaricus and Streptococcus thermophiles, contributing to its health benefits.

Despite its nutritional advantages, including high-quality protein, calcium, and probiotics, yogurt consumption is low in countries like the United States and Brazil, indicating a missed opportunity for improving public health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

History of yogurt and current patterns of consumption. Fisberg, M., Machado, R.[2018]

In a study of 1981 men over a mean follow-up of 20.1 years, high intake of fermented dairy products was associated with a 27% lower risk of coronary heart disease (CHD), while high intake of non-fermented dairy products was linked to a 52% higher risk of CHD.

Specifically, low-fat fermented dairy products were beneficial, showing a reduced risk of CHD, whereas neither high-fat fermented nor any non-fermented dairy products showed a protective effect.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intake of fermented and non-fermented dairy products and risk of incident CHD: the Kuopio Ischaemic Heart Disease Risk Factor Study. Koskinen, TT., Virtanen, HEK., Voutilainen, S., et al.[2019]

Lactic acid bacteria (LAB), particularly L. acidophilus and Bifidobacteria spp, are crucial for the health benefits of fermented dairy products, which should contain more than 10⁶ cfu/g for probiotic claims.

Fermented milks offer various health benefits, including prevention of gastrointestinal infections, reduction of cholesterol levels, and are suitable for lactose intolerant individuals, highlighting their therapeutic potential and consumer acceptance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fermented milks and milk products as functional foods--a review. Shiby, VK., Mishra, HN.[2019]

In a study involving 13 healthy men with mildly high cholesterol, kefir supplementation for 4 weeks did not lower total cholesterol or other lipid levels, indicating it may not be effective as a cholesterol-lowering agent.

However, kefir did increase the levels of certain beneficial short-chain fatty acids in feces and improved fecal bacterial content, suggesting potential positive effects on gut health despite its lack of impact on cholesterol levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Kefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial [ISRCTN10820810]. St-Onge, MP., Farnworth, ER., Savard, T., et al.[2019]

In a study of 26,445 individuals over 12 years, high intake of fermented milk was associated with a 15% reduced risk of cardiovascular disease (CVD), indicating its potential protective effect.

Cheese intake was linked to decreased CVD risk specifically in women, suggesting that different dairy products may have varying health impacts based on sex.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dairy products and its association with incidence of cardiovascular disease: the Malmö diet and cancer cohort. Sonestedt, E., Wirfält, E., Wallström, P., et al.[2021]

A systematic review of 108 studies found that consumption of yogurt and other fermented milk products is associated with improved health outcomes, including reduced risks of breast and colorectal cancer, type 2 diabetes, and enhanced cardiovascular and gastrointestinal health.

The review supports the idea that yogurt consumption can aid in lactose digestion and tolerance, and suggests that these fermented products should be encouraged in national dietary guidelines due to their overall health benefits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Yogurt, cultured fermented milk, and health: a systematic review. Savaiano, DA., Hutkins, RW.[2021]

Epidemiological studies suggest that yogurt consumption is associated with healthier dietary patterns and a reduced risk of cardiometabolic diseases (CMDs), particularly type 2 diabetes, but there is a lack of randomized controlled trials to confirm these findings.

The review highlights that while yogurt is nutrient-dense and may offer benefits due to its protein, calcium, and bioactive components, the mechanisms behind its protective effects against CMDs remain unclear and require further investigation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Yogurt and Cardiometabolic Diseases: A Critical Review of Potential Mechanisms. Fernandez, MA., Panahi, S., Daniel, N., et al.[2023]

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