A 16-week randomized trial found that eating 60g of mixed nuts daily reduced apolipoprotein B and harmful lipoprotein particle numbers in older adults with overweight or obesity, suggesting a shift toward a less atherogenic lipid profile.
Researchers at an academic medical center conducted a crossover trial with 28 older adults (average age 65, BMI 27.9-28.3) to test whether mixed nuts could improve the particle-level structure of blood lipids. This matters because total cholesterol and LDL-cholesterol numbers don't tell the full story. Two people can have identical cholesterol levels but vastly different cardiovascular risk depending on the size, number, and density of their lipoprotein particles. Small, dense LDL particles and high numbers of VLDL particles are more atherogenic (heart disease promoting) than larger particles at the same cholesterol concentration.
Participants spent 16 weeks eating 60 grams daily of a mixed nut blend (15g each of walnuts, pistachios, cashews, and hazelnuts) in one period, then 16 weeks eating no nuts in another period, with an 8-week washout between them. Researchers used nuclear magnetic resonance spectroscopy to measure not just cholesterol numbers, but the exact composition, size, and count of lipoprotein particles across multiple subclasses.
The nut intervention produced measurable shifts in particle profiles. Apolipoprotein B (ApoB) concentrations dropped by 0.07 g/L. Total cholesterol fell by 0.27 mmol/L and triglycerides by 0.27 mmol/L. More importantly, the number of very large VLDL particles decreased significantly (24 nmol/L reduction, p<0.001), with reductions across all VLDL subclasses. Total LDL particle numbers also dropped, driven primarily by reductions in intermediate-density lipoprotein and large LDL particles. Triglycerides declined across all lipoprotein subclasses.
Critically, the changes were directionally favorable. HDL particles (the protective kind) were unaffected, and the shifts favored fewer large atherogenic particles at the expense of larger, less harmful ones. The researchers characterized the overall pattern as movement toward "a less atherogenic profile," though they stopped short of claiming direct cardiovascular disease prevention since this trial measured particle markers, not clinical outcomes like heart attacks or strokes.
If you're an older adult with overweight or obesity, this study suggests that incorporating a mixed nut regimen into your diet could alter your lipid particle profile in a direction associated with lower cardiovascular risk. The dose tested here (60g daily, or roughly two handfuls) is modest and achievable.
This evidence is strongest for lipoprotein particle composition and weakest for clinical outcomes. The study doesn't prove that eating nuts prevents heart disease, only that it alters the physical characteristics of lipoproteins in ways that are theoretically protective. The change in ApoB is particularly relevant, as ApoB is increasingly recognized as a CVD risk marker that may better predict cardiovascular events than LDL-cholesterol alone.
The use of a diverse nut blend rather than a single nut type hints at potential synergistic benefits, though this trial doesn't isolate which nuts drove the effect. The 16-week duration (longer than many dietary trials) strengthens confidence that these aren't transient changes.
One limitation: the study is small (28 participants completing the protocol), and it's unclear whether effects are identical in younger adults or those with normal weight. The single-blind design also means participants knew whether they were eating nuts, which could introduce expectation effects, though lipoprotein particle composition is an objective marker less susceptible to placebo than subjective symptoms.
| Attribute | Value |
|---|---|
| Study Type | Randomized controlled crossover trial |
| Sample Size | 28 completers (aged 65 ± 3 years) |
| Intervention | 60g mixed nuts daily (15g walnuts, pistachios, cashews, hazelnuts each) |
| Control | No nuts (16 weeks) |
| Duration per Arm | 16 weeks, separated by 8-week washout |
| Primary Outcome | Lipoprotein particle number, size, and composition (NMR spectroscopy) |
| Key Findings | ApoB reduced 0.07 g/L (p=0.009); VLDL particles reduced 24 nmol/L (p<0.001); LDL particle numbers reduced (p=0.044) |
| Journal | Nutrients |
| PubMed ID | 39796442 |
Nutrients. 2024. "Effects of Longer-Term Mixed Nut Consumption on Lipoprotein Particle Concentrations in Older Adults with Overweight or Obesity."
PubMed: https://pubmed.ncbi.nlm.nih.gov/39796442/
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