Meat diets vs. vegetarianism

Anyway, asides from that, how are things with you? Reading or thinking over anything interesting? Take care!

I’ll write to you soon.

[Laird]

A dietary swap that could lengthen your life? Study finds replacing butter with plant-based oils cuts premature death risk by 17 percent by Ryan Jaslow for Mass General Brigham Communications on March 6, 2025.

The researchers examined diet and health data from 200,000 people followed for more than 30 years and found that higher consumption of plant-based oils — especially soybean, canola, and olive oil — was associated with lower total, cancer, and cardiovascular disease mortality, whereas butter use was linked with increased risk of total and cancer mortality. The results are published in JAMA Internal Medicine.

Using statistics to compare death rates across different diet intake levels, the researchers found that participants who ate the most butter had a 15 percent higher risk of dying than those who ate the least. In contrast, those who ate the most plant-based oils had a 16 percent lower risk of death than those who ate the least.

The researchers also did a substitution analysis, which mimics how swapping butter for plant oils would impact health in a feeding trial. They found that substituting 10 grams of butter a day (less than a tablespoon) with equivalent calories of plant-based oils could lower cancer deaths and overall mortality by 17 percent.

Corl et al. (2003) demonstrated that two fatty acids - cis-9, trans-11 CLA, which is derived endogenously from trans-11 18:1 in butter -significantly lower cancer risk in rats (https://doi.org/10.1093/jn/133.9.2893).

However, these beneficial long-chain fatty acids are notably diminished in milk from dairy cows treated with Bovaer. The feed additive 3-nitrooxypropanol (Bovaer) markedly changes the rumen microbiome, and according to Melgar et al. (2020), this results in a significant increase in short-chain fatty acids in milk, while long-chain fatty acids such as cis-9, trans-11 CLA and trans-11 18:1 are reduced (https://doi.org/10.3168/jds.20).

[Laird]

Corl et al. (2003) demonstrated that two fatty acids - cis-9, trans-11 CLA, which is derived endogenously from trans-11 18:1 in butter -significantly lower cancer risk in rats (https://doi.org/10.1093/jn/133.9.2893).

A quick response after some skimming of the paper, without doing a deep dive.

Fine, but:

1. The control was also butter, not plant-based oils, so this has no bearing on the study I shared.
   
2. This study in any case considers cancer risk only, whereas the study I shared took all-cause mortality into account.
   
3. This is a study of rats, and its results might or might not apply to humans too, whereas the study I shared is a study of humans.
   
4. This is a lab study, whereas the study I shared is a real-world study - perhaps not a very important point but worth noting.
   

However, these beneficial long-chain fatty acids are notably diminished in milk from dairy cows treated with Bovaer. The feed additive 3-nitrooxypropanol (Bovaer) markedly changes the rumen microbiome, and according to Melgar et al. (2020), this results in a significant increase in short-chain fatty acids in milk, while long-chain fatty acids such as cis-9, trans-11 CLA and trans-11 18:1 are reduced (https://doi.org/10.3168/jds.20).

The link results in an error. In any case, based simply on what you shared:

Fine again, but, again, this doesn't seem to take plant oils into account at all, so, again, it doesn't seem to have any bearing on the study I shared.

In any case, I should add a clarification that the risk reduction reported in the study I shared is relative; the absolute risk reduction is apparently much smaller.