Lard-based diets, calories and mouse heart mitochondria
What it found
In mice, high-calorie lard-based diets led to heart enlargement and lower activity of two mitochondrial energy complexes, with the fat level itself adding to oxidative stress.
The calorie content, not the fat percentage, seemed to drive most of the heart changes.
What they found
Animal and lab studies
Heart enlargement
Mice on both lard-based diets gained more weight and had thicker heart walls and larger heart muscle cells than mice on standard chow. The two lard groups did not differ from each other in these heart changes.
Mitochondrial energy complexes
Activity of mitochondrial complexes I and III was lower in the hearts of mice on both lard-based diets compared to standard chow. There was no difference between the high-fat and low-fat lard groups.
Oxidative stress marker
Mice on the high-fat lard diet had higher levels of malondialdehyde, a marker of oxidative stress, than mice on the low-fat lard diet or standard chow. The low-fat lard group also had higher levels than the standard chow group.
Fibrosis
The amount of scar tissue (fibrosis) in the heart was not different between the three groups.
Calorie intake
Mice on the lard-based diets ate more calories than mice on standard chow. The high-fat lard group gained more weight than the low-fat lard group.
What the authors conclude
“We assume that changes in cardiac morphology and selective reduction of the OXPHOS complexes activity observed in the HFD- and LFD-fed mice might be related to excessive calories with additional effect of fat content on oxidative stress.”
Also in their conclusions
- They conclude that the heart changes and lower mitochondrial complex activity seen in mice on lard-based diets may be mainly due to the extra calories, with the fat content adding to oxidative stress.
- They suggest that the extra oxidative stress from higher lard fat could, over a longer time than 10 weeks, lead to more heart remodeling and fibrosis.
- They call for more research into how these diets affect heart mitochondria and whether age makes a difference.
How it was done
The authors wanted to know whether eating a lot of saturated and monounsaturated fats from lard harms heart structure and energy production, or whether the harm comes mainly from the extra calories in such diets.
Six-week-old C57BL/6J mice were fed for 10 weeks with a high-calorie diet containing 60% fat from lard, a high-calorie diet with 10% fat from lard, or standard chow with 12% fat and fewer calories. Each group had 7 mice.
What it can’t tell you
- This was a study in mice, so it cannot show what would happen in people eating lard.
- The study lasted only 10 weeks, so it cannot show the effects of eating lard-based diets for many years.
- The authors did not compare lard with other types of fat matched for calories, so the role of fat type versus calories is not fully clear.
Who paid
- Funding
- Funded by NHLBI NIH HHS (from the PubMed record).
- Conflicts
- The authors have declared that no competing interests exist.
- Authors work at
- Center for Integrative Research on Cardiovascular Aging, United States of America
The paper
- Title
- High calories but not fat content of lard-based diet contribute to impaired mitochondrial oxidative phosphorylation in C57BL/6J mice heart
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Emelyanova L, Boukatina A, Myers C, et al (2019). High calories but not fat content of lard-based diet contribute to impaired mitochondrial oxidative phosphorylation in C57BL/6J mice heart. PloS one. doi:10.1371/journal.pone.0217045Free full textPubMed 31265457DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error