More Liver

It's time to celebrate your liver. It's a hard-working organ and it deserves some credit.

One of the liver's most important overall functions is maintaining nutrient homeostasis. It controls the blood level of a number of macro- and micronutrients, and attempts to keep them all at optimal levels.

Here's a list of some of the liver's functions I'm aware of:

• Buffers blood glucose by taking it up or releasing it when needed
• A major storage site for glycogen (a glucose polymer)
  
• Clears insulin from the blood
• Synthesizes triglycerides
• Secretes and absorbs lipoprotein particles ("cholesterol")
• Stores important vitamins: B12, folate, A, D, E, K (that's why it's so nutritious to eat!)
• Stores minerals: copper and iron
  
• Detoxifies the blood
• Produces ketone bodies when glucose is running low
• Secretes blood proteins
• Secretes bile
• Converts thyroid hormones
• Converts vitamin D (D3 --> 25(OH)D3)
  

The liver is an all-purpose metabolic powerhouse and storage depot. In the next post, I'll give you a recipe for it...

Book Review: Blood Sugar 101

I just finished reading "Blood Sugar 101" by Jenny Ruhl. It's a quick read, and very informative. Ruhl is a diabetic who has taken treatment into her own hands, using the scientific literature and her blood glucose monitor to understand blood sugar control and its relationship to health. The book challenges some commonly held ideas about diabetes, such as the notion that diabetics always deteriorate.

She begins by explaining in detail how blood glucose is controlled by the body. The pancreas releases basal amounts of insulin to make glucose available to tissues between meals. It also releases insulin in response to carbohydrate intake (primarily) in two bursts, phase I and phase II. Phase I is a rapid response that causes tissues to absorb most of the glucose from a meal, and is released in proportion to the amount of carbohydrate in preceding meals. Phase II cleans up what's left.

In a person with a healthy pancreas, insulin secretion will keep blood glucose under about 130 mg/dL even under a heavy carbohydrate load. The implications of this are really interesting. Namely, that blood glucose levels will not be very different between a person who eats little carbohydrate, and one who eats a lot, as long as the latter has a burly pancreas and insulin-sensitive tissues.

Most Americans don't have such good control however, hence the usefulness of low-carbohydrate diets. This begs the question of why we lose blood sugar control. Insulin resistance seems like a good candidate, maybe preceded by leptin resistance. As you may have noticed, I'm starting to think the carbohydrate per se is not the primary insult. It's probably something else about the diet or lifestyle that causes carbohydrate insensitivity. Grain lectins are a good candidate in my opinion, as well as inactivity.

Diabetics can have blood glucose up to 500 mg/dL, that remains elevated long after it would have returned to baseline in a healthy person. Ruhl asserts that elevated blood sugar is toxic, and causes not only diabetic complications but perhaps also cancer and heart disease.

Heart attack incidence is strongly associated with A1C level, which is a rough measure of average blood sugar over the past couple of months. It makes sense, although most of the data she cites is correlative. They might have seen the same relationship if they had compared heart attack risk to fasting insulin level or insulin resistance. It's difficult to nail down blood sugar as the causative agent. More information from animal studies would have been helpful.

Probably the most important thing I took from the book is that the first thing to deteriorate is glucose tolerance, or the ability to pack post-meal glucose into the tissues. It's often a result of insulin resistance, although autoimmune processes seem to be a factor for some people. Doctors often use fasting glucose to diagnose diabetes and pre-diabetes, but typically you are far gone by the time your fasting glucose is elevated!

I like that she advocates a low-carbohydrate diet for diabetics, and lambasts the ADA for its continued support of high-carbohydrate diets.

Overall, a good book. I recommend it!

Olive Oil Buyer's Guide

Olive oil is one of the few good vegetable oils. It is about 10% omega-6 (n-6) fatty acids, compared to 50% for soybean oil, 52% for cottonseed oil and 54% for corn oil. Omega-6 fatty acids made up a smaller proportion of calories before modern times, due to their scarcity in animal fats. Beef suet is 2% n-6, butter is 3% and lard is 10%. Many people believe that excess n-6 fat is a contributing factor to chronic disease, due to its effect on inflammatory prostaglandins. I'm reserving my opinion on n-6 fats until I see more data, but I do think it's worth noting the association of increased vegetable oil consumption with declining health in the US.

Olive oil is also one of the few oils that require no harsh processing to extract. As a matter of fact, all you have to do is squeeze the olives and collect the oil. Other oils that can be extracted with minimal processing are red palm oil (9% n-6), hazelnut oil (10% n-6) and coconut oil (2% n-6). These are also the oils I consider to be healthy. Due to the mild processing these oils undergo, they retain their natural vitamin and antioxidant content.

You've eaten corn, so you know it's not an oily seed. Same with soybeans. So how to they get the oil out of them? They use a combination of heat and petroleum solvents. Then, they chemically bleach and deodorize the oil, and sometimes partially hydrogenate it to make it more shelf-stable. Hungry yet? This is true of all the common colorless oils, and anything labeled "vegetable oil".

Olive oil is great, but don't run out and buy it just yet! There are different grades, and it's important to know the difference between them. The highest grade is extra-virgin olive oil, and it's the only one I recommend. It's the only grade that's not heated or chemically refined in any way. Virgin olive oil, "light" olive oil (refers to the flavor, not calories), "pure" olive oil, or simply olive oil all involve different degrees of chemical extraction and/or processing. This applies primarily to Europe. Unfortunately, the US is not part of the International Olive Oil Council (IOOC), which regulates oil quality and labeling.

The olive oil market is plagued by corruption. Much of the oil exported from Italy is cut with cheaper oils such as colza. Most "Italian olive oil" is actually produced in North Africa and bottled in Italy, and may be of inferior quality. The USDA has refused to regulate the market so they get away with it. If you find a deal on olive oil that looks too good to be true, it probably is.

Only buy from reputable sources. Look for the IOOC seal, which guarantees purity, provenance and freshness. IOOC olive oil must contain less than 0.8% acidity. Acidity refers to the percentage of free fatty acids (as opposed to those bound in triglycerides), a measure of damage to the oil. Fortunately, the US has a private equivalent to the IOOC, the California Olive Oil Council (COOC). The COOC seal ensures provenance, purity and freshness just like the IOOC seal. It has outdone the IOOC in requiring less than 0.5% acidity. COOC-certified oils are more expensive, but you know exactly what you're getting.

Thanks to funadium for the CC photo

Real Food V: Sauerkraut

Sauerkraut is part of a tradition of fermented foods that reaches far into human prehistory. Fermentation is a means of preserving food while also increasing its nutritional value. It increases digestibility and provides us with beneficial bacteria, especially those that produce lactic acid. Raw sauerkraut is a potent digestive aid, probably the reason it's traditionally eaten with heavy food.

Sauerkraut is produced by a process called ‘anaerobic’ fermentation, meaning ‘without oxygen’. It’s very simple to achieve in practice. You simply submerge the cabbage in a brine of its own juices and allow the naturally present bacteria to break down the sugars it contains. The process of ‘lacto-fermentation’ converts the sugars to lactic acid, making it tart. The combination of salt, anaerobic conditions, and acidity makes it very difficult for anything to survive besides the beneficial bacteria, so contamination is rare. If it does become contaminated, your nose will tell you as soon as you taste it.

Store-bought sauerkraut is far inferior to homemade. It's soggy and sterile. Ask a German: unpasteurized kraut is light, crunchy and tart!

My method is inexpensive and requires no special equipment. I've tested it many times and have never been disappointed.

Materials

• Wide-mouth quart canning jars (cheap at your local grocery store)
• Beer bottles with the labels removed, or small jars that fit inside the canning jars
• Three tablespoons of sea salt (NOT iodized table salt-- it's fatal to our bacteria)
• Five pounds of green cabbage

Recipe

1. Chop cabbage thinly. Ideally the slices should be 2 mm or so wide, but it doesn’t matter very much. You can use a food processor, mandolin or knife.
2. Put all the cabbage together in a large bowl and add the salt. If the salt is not very dense (sometimes finely ground sea salt can be fluffy), you can add up to 5 tablespoons total. Mix it around with your hands. Taste some. It should be good and salty.
3. Let the salted cabbage sit in the bowl for 30 minutes or so. It should be starting to get juicy.
4. Pack the cabbage tightly into the canning jars. Leave 2-3 inches at the top of the jar. When you push on the cabbage in the jar, you should be able to get the brine to rise above the cabbage. Try to get rid of air bubbles.
5. Put water into the beer bottles and place them into the canning jars. The weight of the bottles will keep the cabbage under the brine. It’s okay that some of the brine is exposed to the air; the cabbage itself is protected.
6. Let it sit for 2 weeks at room temperature! As the fermentation proceeds, bubbles will form and this will raise the level of the brine. This is normal. You might get some scum on top of the liquid; just check for this and scrape it off every few days. It won’t affect the final product. If the brine drops to the level of the cabbage, add salt water (1 tsp/cup, non-chlorinated water) to bring it back up.
7. Taste it! It should be tart and slightly crunchy, with a fresh lactic acid flavor. If fully fermented, it will keep in the fridge for a long time.

Here are some photos from making sauerruben, which is like sauerkraut but made with turnips:

Leptin

I've been puzzled by an interesting question lately. Why is it that certain cultures are able to eat large amounts of carbohydrate and remain healthy, while others suffer from overweight and disease? How do the pre-industrial Kuna and Kitavans maintain their insulin sensitivity while their bodies are being bombarded by an amount of carbohydrate that makes the average American look like a bowling ball?

I read a very interesting post on the Modern Forager yesterday that sent me on a nerd safari through the scientific literature. The paper that inspired the Modern Forager post is a review by Dr. Staffan Lindeberg. In it, he attempts to draw a link between compounds called lectins, found in grains (among other things), and resistance to the hormone leptin. Let's take a step back and go over some background.

One of the most-studied animal models of obesity is called the "Zucker" rat. This rat has a missense mutation in its leptin receptor gene, causing it to be nonfunctional. Leptin is a hormone that signals satiety, or fullness. It's secreted by fat tissue. The more fat tissue an animal has, the more leptin it secretes. Normally, this creates negative feedback that causes it to eat less when fat begins to accumulate, keeping its weight within a narrow range.

Zucker rats secrete leptin just fine, but they lack leptin receptors in their brain. Their blood leptin is high but their brain isn't listening. Thus, the signal to stop eating never gets through and they eat themselves to morbid obesity. Cardiovascular disease and diabetes follow shortly thereafter, unless you remove their visceral fat surgically.

The reason Zucker rats are so interesting is they faithfully reproduce so many features of the disease of civilization in humans. They become obese, hypometabolic, develop insulin resistance, impaired glucose tolerance, dyslipidemia, diabetes, and cardiovascular disease. Basically, severe metabolic syndrome. So here's a rat that shows that leptin resistance can cause something that looks a whole heck of a lot like the disease of civilization in humans.

For this model to be relevant to us, we'd expect that humans with metabolic syndrome should be leptin-resistant. Well what do you know, administering leptin to obese people doesn't cause satiety like it does in thin people. Furthermore, elevated leptin predicts the onset of obesity and metabolic syndrome. It also predicts insulin resistance. Yes, you read that right, leptin resistance may come before insulin resistance.

Interestingly enough, the carbohydrate-loving Kitavans don't get elevated leptin like europeans do, and they don't become overweight, develop insulin dysfunction or the metabolic syndrome either. This all suggests that leptin may be the keystone in the whole disease process, but what accounts for the differences in leptin levels between populations?