Seth’s blog

My recent heart scan score was about 50% less than you’d expect from an earlier score. Why the improvement?

During the year between the two tests, I’d made one big change: eat much more animal fat. That’s the obvious explanation. Three things support it:

1. Mozaffarian et al., as I blogged, found a similar result.

2. The animal fat (pork fat and butter) had both produced large immediate improvements when I began to eat them. The pork fat had improved my sleep; the butter, my arithmetic scores. This sort of large immediate effect we associate with the supply of a missing necessary nutrient — giving Vitamin C to someone with scurvy, for example. My brain, at least, needed much more animal fat than I’d been eating. Different parts of the body need different nutrients, sure, but they all must work well with the same set of nutrients. If Nutrient X helps one part of the body, it is more likely to help another part.

3. My initial score put me at the 50th percentile for my age. I’d had an unusual diet for a long time. I stopped eating bread, potatoes, rice, pasta, and dessert 13 years ago. I’d started consuming lots of omega-3 and fermented foods a few years earlier. It was possible that those other changes produced improvement but if so it was a strange coincidence that, as my score got better and better over the years, I happened to measure it for the first time just when it crossed the 50th percentile.

This explanation makes a prediction: If you greatly increase your animal-fat intake, your heart scan score should improve. A commenter said what he’d read on paleo-diet forums supported this prediction: “If you hang out in the paleo/low carb forums, you see this kind of thing a lot.”

I posted yesterday that a recent heart scan found my arteries about 50% less calcified than a previous scan predicted. Apparently the improvement was due to eating much more animal fat (pork fat and butter).

In 2004, an American Journal of Clinical Nutrition article found something similar: heart disease progressed less in women who ate more saturated fat. “In postmenopausal women with relatively low total fat intake, a greater saturated fat intake is associated with less progression of coronary atherosclerosis,” the authors wrote. Here’s how they saw this finding:

The inverse association between saturated fat intake and atherosclerotic progression was unexpected. However, this finding should perhaps be less surprising. Ecologic and animal experimental studies showed positive relations between saturated fat intake and CHD risk (8). However, cohort studies and clinical trials in humans have been far less consistent (9 –12). Furthermore, most studies of dietary fat and CHD risk have been performed in men (15, 16). The relations in women—particularly postmenopausal women—are much less well-established, and evidence from dietary intervention trials suggests that diets low in saturated fat may have different effects on CHD risk factors in women (15, 17–22).

In their study, women with the highest intake of saturated fat did not get worse during the study period, whereas women with lower intakes did get worse.

An editorial about this study described some of the evidence that supports the “article of faith” that “saturated fat . . . accelerates coronary artery disease”:

One of the earliest and most convincing studies of the better efficacy of unsaturated than of saturated fat in reducing cholesterol and heart disease is the Finnish Mental Hospital Study conducted in the 12 y between 1959 and 1971. In this study, the usual high-saturated-fat institutional diet was compared with an equally high-fat diet in which the saturated fat in dairy products was replaced with soybean oil and soft margarine and polyunsaturated fats were used in cooking. Each diet was provided for 6 y and then the alternate diet was provided for the next 6 y. After a comparison of the effects of the 2 diets in both men and women, the incidence of coronary artery disease was lower by 50% and 65% after the consumption of polyunsaturated fat in the 2 hospitals.

My results make the results of that earlier study exceedingly puzzling. I found a large change in one direction; the Finnish study found a large effect in the opposite direction. Given the huge effect (50% or 65% reduction) observed in the Finnish study, it is hard to understand why “cohort studies and clinical trials in humans have been far less consistent”.

One and a half years ago, in February 2009, I got a heart scan. It’s an X-ray measurement of how calcified your arteries are. Persons with high scores are much more likely to have a heart attack than persons with low scores. Scores in the hundreds are dangerous. Tim Russert, who died at age 58 of a heart attack, had a score of about 200 ten years before his death. Above age 40, the scores typically increase about 25% per year. That puts Russert’s score when he died at around 2000.

A few weeks ago I got another scan, at the same place with the same machine. Here are my scores. February 2009: 38 (about 50th percentile for my age). August 2010: 29 (between 25th & 50th percentile). In other words: 47% lower than expected. The earlier scan detected 3 “lesions”; the recent scan detected 2. The woman who runs the scanning center — HeartScan, in Walnut Creek, California — told me that decreases in this score are very rare. About 1 in 100, she said.

The only big lifestyle change I made between the two scans is to eat much more animal fat. After I found that pork fat improved my sleep, I started to eat a large serving of pork belly (with 80-100 g of fat) almost every day. Later I switched to 60 g of butter every day. The usual view, of course, is that to eat so much animal fat is v v bad and will “clog” my arteries. In fact, the reverse happened. Judging from this, the change was v v good.

This recent study from Japan found that middle-aged men and women who ate more saturated fat had a lower risk of stroke. The rate of strokes was 30% lower in the highest intake quintile compared to the lowest quintile. There was a non-significant reduction in heart disease.

Other big differences were correlated with saturated fat intake. For example, those in the highest quintile had more college education than those in the lowest quintile and were more likely to do sports >1 hr/week. These data by themselves won’t convince anyone that saturated fats are beneficial. But they should push you in that direction. Contrary to what you’ve heard a million times.

As far as I can tell, eating lots of butter has lowered my blood pressure. High blood pressure is associated with greater risk of stroke.

Although pig fat certainly helped me (I slept better), I’ve found butter is even better. Butter has considerably more saturated fat than pig fat.  The fat in butter is  60% saturated fat, whereas pig fat is 40% saturated fat. My consumption of 60 g/day of butter gives me 36 g/day saturated fat. In this study, persons in the highest quintile of intake averaged 20 g/day. The highest intake in the whole study (60,000 people) was 40 g/day. In addition to butter, I eat cheese, whole-fat yogurt, and meat, so I’m surely higher than that.

Via Whole Health Source.

I am a big fan of pork belly. Whenever I see it on a menu I order it. The mayor of Chongqing (population 32 million) recently made headlines with a speech whose main point was

改善民生不只是吃红烧肉穿漂亮衣服

Which means: Better living standards is not just eating hong shao rou wearing beautiful clothes. Hong shao rou is pork belly braised in a red sauce. Maybe my favorite Chinese dish. Supposedly Chairman Mao’s favorite dish. I’m glad he said “not just” rather than “not”.