Rabbits on a High-Saturated Fat Diet Without Added Cholesterol

I just saw another study that supports my previous post Animal Models of Atherosclerosis: LDL. The hypothesis is that in the absence of excessive added dietary cholesterol, saturated fat does not influence LDL or atherosclerosis in animal models, relative to other fats (although omega-6 polyunsaturated oils do lower LDL in some animal models). This appears to be consistent with what we see in humans.

In this study, they fed four groups of rabbits different diets:

1. Regular low-fat rabbit chow
2. Regular low-fat rabbit chow plus 0.5 g cholesterol per day
3. High-fat diet with 30% calories as coconut oil (saturated) and no added cholesterol
4. High-fat diet with 30% calories as sunflower oil (polyunsaturated) and no added cholesterol

LDL at 6 months was the same in groups 1, 3 and 4, but was increased more than 20-fold in group 2. It's not the fat, it's the fact that they're overloading herbivores with dietary cholesterol!

Total cholesterol was also the same between all groups except the cholesterol-fed group. TBARS, a measure of lipid oxidation in the blood, was elevated in the cholesterol and sunflower oil groups but not in the chow or coconut groups. Oxidation of blood lipids is one of the major factors in atherosclerosis, the vascular disease that narrows arteries and increases the risk of having a heart attack. Serum vitamin C was lower in the cholesterol-fed groups but not the others.

This supports the idea that saturated fat in the absence of excess dietary cholesterol does not necessarily increase LDL, and in fact in most animals it does not.

Merry Christmas!

Hello, world!

Well, I've just started my technical/research blog.

Why?

I already have a personal blog, which is (I hope) used to be read by a number of my friends. In recent time I noticed that I had begun post a lot of technical stuff my friends were not interested in. Also, that blog is in Russian, which limits its audience. So, I preferred not to change the blog policy but create a new blog. It was also Boris Yangel's amazing blog that inspired me to create mine.

Computer blindness?

Well, yes. Folks who know me might already divine that the blog is primarily about computer vision, and they are certainly right. I chose such a fancy name because computer vision is somewhat disappointing. Let me explain.

Do you remember that story when Marvin Minsky at MIT asked his student to teach a computer understand the scene retrieved from a camera during the 1966 summer break? Unsurprisingly, the student failed. Moreover, the general task is far from being solved even now. That days computers were slow, and AI scientists thought that performing logical inference is way more complicated than just scene analysis. Now, we have Prolog and a pile of different verification systems (thanks to the university curriculum -- we used some of them), but a computer is not able to recognize even simple object categories on different classes of images (e.g. relatively robust face detection was done only in early 2000s by Viola and Jones).

Actually, not only Minsky was misled. If you are a vision researcher, when you tell people about your research, they are likely to reply: "Is that all you can? Man, it's simple!" Sure, it is simple for you to figure out that it is a cow on the meadow, not a horse, but try to explain it to computer! It is actually a problem in our lab: when vision guys try to defend a Masters/PhD thesis in front of the committee (which consists of folks who do research in computer hardware, system programming etc), and the committee is usually not impressed by the results, because they think it is not too difficult.

Okay, you've got the point. Computers are blind, and we should cope with that.

Next. Do you know, what's the difference between computer vision of 1980s and modern computer vision? In 80s, they used to solve particular problems, not general ones. They could implement quite a decent vision system that performed its task, but it could not be transferred to another domain. Nowadays, such approach is no more scientific, while it is still good for engineers. Today, computer vision science is about general tasks. It became possible because of extensive using of machine learning methods (a lot of them were developed in '90s). Vision is nothing without learning now. I hope you've got this point too: Vision + Learning = Forever Together. That's why my blog cannot ignore machine learning issues.

What else? Programming language is a tool, but it can be interesting per se. I am about to finish a 5-year university programme in Computer Science, so I have been being taught different language concepts and programming paradigms, and I find it interesting sometimes. That is another possible topic.

Finally,

Subscribe me, read me and comment me. Everybody is welcome! Let it roll!

It's all in the training

Merry Christmas and Happy New Year

Tomat Alternatif Pengganti Aspirin
By Republika Newsroom
Rabu, 23 Desember 2009 pukul 11:40:00




LONDON--Kandungan gel atau gelatin alami yang terdapat dalam tomat telah diidentifikasi peneliti di Inggris sebagai kunci penting untuk kesehatan. Gel ini diyakini para peneliti mampu melancarkan sirkulasi darah.

Secara karakteristik, gel pada tomat umumnya berwarna dan memiliki rasa. Peneliti di Inggris bahkan meyakini bahwa gel itu bila dibaurkan pada makanan tidak akan mengubah komponen dasarnya.

Komisi Kesehatan Uni Eropa yang telah menerima laporan dari peneliti asal Inggris terkait kandungan pada gel tomat yang mampu memperlancar peredaran darah, telah menyetujui Penggunaan getah ini dalam bentuk obat kemasan.

Sementara itu, jutaan masyarakat berusia lanjut telah mengkonsumsi aspirin dalam dosis rendah guna memperlancar peredaran darah. Meski begitu, peneliti merasa khawatir penggunaan aspirin meninggalkan efek seperti pendarahan pada perut dan pembentukan bisul.

Profesor Asim Dutta-Roy dari Rowwet Institute di Aberdeen, Skotlandia mengatakan Fruitflow (nama gel tomat itu)sangat baik untuk digunakan sebagai pengganti aspirin.

"Hingga kini, tidak terlihat efek negatif yang berhasil terekam saat percobaan pengembangan Fruitflow berlangsung," tukasnya seperti dilansir Telegraph, Rabu (23/12).

Pernyataan Dutta-Roy juga didukung keberhasilan fruitflow memberikan efek terhadap peredaraan darah hanya 3 jam setelah dikonsumsi dan manfaatnya pada tubuh berlangsung hingga 18 Jam. Hasil ini tentu ideal untuk dikonsumsi setiap hari.

Dalam perkembangannya, fruitflow tidak hanya dikonsumsi dalam bentuk tablet atau kapsul tapi juga jus. Fruitflow sendiri sudah dijual bebas diberbagai apotik atau toko obat. cr2/rin

What's the Ideal Fasting Insulin Level?

[2013 update.  I'm leaving this post up for informational purposes, but I think it's difficult to determine the "ideal" insulin level because it depends on a variety of factors including diet composition.  Also, insulin assays are not always comparable to one another, particularly the older assays, so it's difficult to compare between studies]

Insulin is an important hormone. Its canonical function is to signal cells to absorb glucose from the bloodstream, but it has many other effects. Chronically elevated insulin is a marker of metabolic dysfunction, and typically accompanies high fat mass, poor glucose tolerance (prediabetes) and blood lipid abnormalities. Measuring insulin first thing in the morning, before eating a meal, reflects fasting insulin. High fasting insulin is a marker of metabolic problems and may contribute to some of them as well.

Elevated fasting insulin is a hallmark of the metabolic syndrome, the quintessential modern metabolic disorder that affects 24% of Americans (NHANES III). The average insulin level in the U.S., according to the NHANES III survey, is 8.8 uIU/mL for men and 8.4 for women (2). Given the degree of metabolic dysfunction in this country, I think it's safe to say that the ideal level of fasting insulin is probably below 8.4 uIU/mL.

Let's dig deeper. What we really need is a healthy, non-industrial "negative control" group. Fortunately, Dr. Staffan Lindeberg and his team made detailed measurements of fasting insulin while they were visiting the isolated Melanesian island of Kitava (3). He compared his measurements to age-matched Swedish volunteers. In male and female Swedes, the average fasting insulin ranges from 4-11 uIU/mL, and increases with age. From age 60-74, the average insulin level is 7.3 uIU/mL.

In contrast, the range on Kitava is 3-6 uIU/mL, which does not increase with age. In the 60-74 age group, in both men and women, the average fasting insulin on Kitava is 3.5 uIU/mL. That's less than half the average level in Sweden and the U.S. Keep in mind that the Kitavans are lean and have an undetectable rate of heart attack and stroke.

Another example from the literature are the Shuar hunter-gatherers of the Amazon rainforest. Women in this group have an average fasting insulin concentration of 5.1 uIU/mL (4; no data was given for men).

I found a couple of studies from the early 1970s as well, indicating that African pygmies and San bushmen have rather high fasting insulin. Glucose tolerance was excellent in the pygmies and poor in the bushmen (5, 6, free full text). This may reflect differences in carbohydrate intake. San bushmen consume very little carbohydrate during certain seasons, and thus would likely have glucose intolerance during that period. There are three facts that make me doubt the insulin measurements in these older studies:

1. It's hard to be sure that they didn't eat anything prior to the blood draw.
2. From what I understand, insulin assays were variable and not standardized back then.
3. In the San study, their fasting insulin was 1/3 lower than the Caucasian control group (10 vs. 15 uIU/mL). I doubt these active Caucasian researchers really had an average fasting insulin level of 15 uIU/mL. Both sets of measurements are probably too high.

Now you know the conflicting evidence, so you're free to be skeptical if you'd like.

We also have data from a controlled trial in healthy urban people eating a "paleolithic"-type diet. On a paleolithic diet designed to maintain body weight (calorie intake had to be increased substantially to prevent fat loss during the diet), fasting insulin dropped from an average of 7.2 to 2.9 uIU/mL in just 10 days. This is despite a substantial intake of carbohydrate, including fruit and vegetable sugars.  The variation in insulin level between individuals decreased 9-fold, and by the end, all participants were close to the average value of 2.9 uIU/mL. This shows that high fasting insulin is correctable in people who haven't yet been permanently damaged by the industrial diet and lifestyle. The study included men and women of European, African and Asian descent (7).

One final data point. My own fasting insulin, earlier this year, was 2.3 uIU/mL. I believe it reflects a good diet, regular exercise, sufficient sleep, and a relatively healthy diet growing up. It does not reflect: carbohydrate restriction, fat restriction, or saturated fat restriction.

So what's the ideal fasting insulin level? My current feeling is that we can consider anything between 2 and 6 uIU/mL within our evolutionary template.