Type 2 diabetes: which are the safest carbohydrates?

In my previous post, I stated that people with type 2 diabetes should eat ~100g/day of carbohydrate.

Beans means...

See International table of glycemic index and glycemic load values: 2002. Below is a list of carbohydrates that have a low glycaemic load, or GL (GL = glycaemic index * grams of carbohydrate in the serving).

Non-nutritive sweeteners:

It's often claimed that non-nutritive sweeteners produce a cephalic phase insulin response. The mere anticipation of eating produces a cephalic phase insulin response. See How neural mediation of anticipatory and compensatory insulin release helps us tolerate food. An insulin response suppresses serum NEFAs, so it's not all bad.

Sugars and Sugar alcohols:

Fructose is not recommended for type 2 diabetics, as it "barges its way" into the liver via Glu-T5 and fructokinase. Type 2 diabetics who have a high fasting serum glucose level almost certainly already have full liver glycogen stores, so adding to them isn't advisable.
Lactose has a virtually zero GL, isn't very sweet and has/hasn't a laxative effect in large quantities (lactase-dependent). Heating lactose turns it into lactulose.
Lactulose has a virtually zero GI, is sweet and has a laxative effect in large quantities.
Galactose is not recommended, as large amounts may accelerate ageing.
D-mannose has a virtually zero GI, is sweet and doesn't have a laxative effect in large quantities. It can be used to treat urinary tract infections (UTIs) caused by e.coli, due to the fact that the kidneys filter it out of the blood and pass it out in the urine. Mannose in urine reduces the adhesion of e.coli to the inside wall of the urinary tract. See Intervening with urinary tract infections using anti-adhesives based on the crystal structure of the FimH-oligomannose-3 complex.
Trehalose has a virtually zero/moderate GI, is sweet and has/hasn't a laxative effect in large quantities (trehalase-dependent).

Lactitol has a virtually zero GI and a laxative effect in large quantities.
Sorbitol has a virtually zero GI and a laxative effect in large quantities.
Xylitol has a virtually zero GI, minty overtones and reduces dental plaque. However, it has a laxative effect in large quantities.
Erythritol has a virtually zero GI, minty overtones and is wee'ed-out like D-mannose, so it doesn't have a laxative effect in large quantities.

Starches:

Don't overcook starches, as that raises their GL. Al-dente is best.
Gram dhal a.k.a. chana dal.
Long-grain rice. Refrigerating cooked rice for 24 hours slightly lowers the GL by forming resistant starch. See item 275 in the table in the first link.
New potatoes. Refrigerating cooked new potatoes for 24 hours drastically lowers the GL by forming resistant starch. See item 605 in the table in the first link. Old potatoes can be used, but they probably won't taste as good.
Bürgen Soya & Linseed bread has 11.9g of carbs/slice.
Pearl barley.
Sweet corn.
Beans.
Chickpeas.
Lentils.
Peas.
Fettuccine.
Egg noodles.
Starchy nuts e.g. peanuts , cashews and chestnuts.
Vegetables.
Root vegetables.
Raw carrots.

The above lists also apply to people with Type 1 diabetes who are having difficulty keeping their blood glucose between 3 and 8mmol/L.

How eating sugar & starch can lower your insulin needs.

This is a bookmarking post. Jason Sandeman is a chef who has a couple of web-sites at Well Done Chef! and Jason Sandeman — Real Food For Your Life. He has Latent Autoimmune Diabetes of Adulthood (LADA), which has resulted in a total loss of his pancreatic beta cells which means that he has to take insulin.

Now, it's generally believed in low-carb circles (and by myself) that people with Type 1 Diabetes Mellitus (T1DM) should minimise their intake of sugary & starchy carbohydrates as these promote wild fluctuations in blood glucose. See The problem with Diabetes.

Jason wrote the following comment on Richard Nikoley's blog. The relevant part is as follows:-
"Even more weird – now that I have introduced the starches into the diet – I have actually got better control now. I thought my insulin needs would go up – but they haven’t. They’ve gone down."

To which I replied:-"How about this for an explanation? You now have a well-controlled glucose input to your circulation via diet, which has suppressed the poorly-controlled glucose input to your circulation via hepatic glucose production."

Hepatic glucose production (HGP) is increased by Glucagon, Cortisol & Adrenaline/Epinephrine. These are secreted as blood glucose level falls below certain values in order to keep our brains alive. See Blood Glucose, Insulin & Diabetes.

As keeping our brains alive is rather important (!), the mechanism is fairly crude in operation and blood glucose can overshoot in a positive direction, as a bit of glycation is less harmful than brain death. See "Funny turns": What they aren't and what they might be. Hyperglycaemia requires insulin to lower blood glucose back to the normal range.

Therefore, eating some (but not too much) sugar & starch can result in lower blood glucose level and lower insulin secretion. Eating fibre/fiber (a carbohydrate) is also good for keeping blood glucose low, as only just mentioned in Fiber and Insulin Sensitivity. Ain't the human body weird?

Fiber and Insulin Sensitivity.

Bluddy Americans. It's Fibre! But anyway....

Stabby the Raccoon posted the following study in a comment on CarbSane's blog. I thought that it was so interesting that I am linking to it here.

Fiber and Insulin Sensitivity.

This study has built-in cognitive dissonance.

The first Fig. suggests that cereal fibre is associated with a much lower RR for Type 2 Diabetes Mellitus (T2DM) and that fruit & veggie fibre aren't.

Schulze et al. 2007: Cereal Fiber RR = 0.6 - 0.7. Fruit Fiber RR = 0.9 - 1.05. Vegetable Fiber RR = 0.95 - 1.15 approx.

The next table suggests otherwise.

Andersson et al., 2007: Whole grain diet contained 112 g/d of whole grain, 18 g fiber. No effect of whole grains on insulin sensitivity.

Ebeling et al., 1988: 5 g/d granulated guar. No effect on insulin sensitivity.

Johnston et al., 2010: Resistant starch supplement -40g/d. Improved insulin sensitivity with resistant starch.

Landin et al., 1992: 30 g/d granulated guar, given in 3-10 g doses. Improved insulin sensitivity with guar diet.

Maki et al., 2011: High-resistant starch diet- 30 g/d, Low-resistant starch diet- 15 g/d. Improved insulin sensitivity with both resistant starch diets, but effect only reached statistical significance for men.

Nilsson et al., 2008: White bread enriched with barley fiber and 8g resistant starch, Barley kernel based bread. Improved glucose tolerance with resistant starch.

Pouteau et al., 2010: 28 g/d acetogenic fibers (acacia gum and pectin). No effect on insulin sensitivity.

Robertson et al., 2003: High-resistant starch diet- 60 g/d. Improved insulin sensitivity with resistant starch.

Weickert et al., 2006: Fiber-enriched with 31.2 g insoluble fiber. Improved insulin sensitivity with increased insoluble fiber.

In conclusion, the resistant starches found in high-amylose rices such as Basmati, refrigerated boiled rice & boiled potatoes, also rye & barley breads are beneficial in terms of reducing your RR for T2DM. Watch out, though. Too much dietary resistant starch can cause colic, flatulence & diarrhoea if your intestinal bacteria are knackered. You want fermentation to short-chain fatty acids to occur, not osmotic laxation! See Genetics of Food Intolerance.

Carbohydrates: Dogs' Doodads or Spawn of Satan?

Depending on which side of the fence you're on, Carbohydrates are either the Dogs' Doodads or the Spawn of Satan. As I get older, I prefer to sit on the fence. Let's start with the basics.

What are Carbohydrates?
Carbohydrates are so named because they have the generic formula (CH2O)n. C is carbon and H2O is water hence Carbo-Hydrate. There are several different types.

1) Sugars. There are monosaccharides, the most common being Glucose (a.k.a. Dextrose), Fructose and Galactose. There are disaccharides, the most common being Sucrose, Lactose and Maltose. Disaccharides are 2 monosaccharides linked by a glycosidic bond formed by a condensation reaction (removal of a water molecule, usually by an enzyme). Disaccharides have to be hydrolysed (have a water molecule added back in, usually by an enzyme) into monosaccharides before they can be absorbed in the gut.
Sugars are simple carbohydrates.

2) Starches. These are chains of glucose molecules linked by glycosidic bonds. Starches have to be hydrolysed into glucose molecules before they can be absorbed. There are unbranched chains like amylose which is also known as resistant starch. There are branched chains like amylopectin and maltodextrin. Glycogen is a branched chain "animal starch" that is synthesised inside muscle and liver cells and which can be rapidly converted back into glucose inside cells.

3) Non-Starch Polysaccharides (NSPs). These are also known as fibre/fiber and there are 2 types: soluble (e.g. pectin, beta-glucan & cellulose) and insoluble (e.g. bran). These aren't absorbed, but gut bacteria can feed on soluble fibre/fiber. Starches and NSPs are complex carbohydrates.

For more information, see http://en.wikipedia.org/wiki/Carbohydrate

The amount of carbohydrate that someone needs varies from person to person and increases with the intensity and volume of exercise done. See Everyone is Different. What are the best carbs to eat? "Complex" ones from "wholegrain" cereals? Not necessarily.

Simple vs Complex
TV ads for breakfast cereals bang on about the wholegrain goodness of complex carbohydrates releasing energy slowly. The terms "Simple" and "Complex" actually refer purely to the chemical structure of a carbohydrate and have nothing to do with how fast they turn into blood glucose in the body. The Glycaemic Index (GI) (or Glycemic Index if you're American) relates to how fast carbohydrates turn into blood glucose in the body. See http://www.mendosa.com/gilists.htm for a list of 750 foods and their GI & GL (GL = Glycaemic Load = GI/100 x carb content per serving). Here are a few extracts. Note: a GI of 55 is low; a GL of 10 is low.

The last three items in the list are all simple carbs. As you can see, some wholegrain complex carbs turn into blood sugar faster than simple carbs. This because the wholegrains have been ground into powder which is rapidly digested and absorbed, despite the presence of fibre/fiber.

As fructose has such a low GI, does this mean that we can eat as much of it as we like? No. When we eat fructose, it passes from the small intestine into the portal vein and goes straight to the liver. As liver cells contain an enzyme called fructokinase (which has a high affinity for fructose), all dietary fructose is absorbed by the liver where it tops-up liver glycogen. Liver glycogen is also topped-up by glucose (obtained from the digestion of starchy carbs). Once liver glycogen stores are full, any further fructose is converted into.......triglycerides. High serum triglycerides are heart-unhealthy. See Cholesterol And Coronary Heart Disease.

Why is GI important? When we eat carbohydrates, they raise blood glucose levels. Pancreatic beta cells secrete a hormone called insulin, which allows more glucose to pass into cells (by moving Glu-T4 transporters inside the cells). When more glucose enters cells, glucose levels in the blood fall. It's a negative feedback loop. For millions of years, we lived on a diet of natural, unrefined carbohydrates and so the secretion of insulin never had to change blood glucose levels very rapidly.

When unnatural, refined, high-GI carbs are eaten, blood glucose levels rise much faster. This results in over-secretion of insulin (hyperinsulinaemia). This shuttles too much glucose into cells and results in.......low blood glucose. Rapidly-falling and low blood glucose levels cause feelings of severe hunger and cravings to eat more carbs. It's a vicious circle. Hyperinsulinaemia also has other bad effects on the body. See http://www.mercola.com/2001/jul/14/insulin.htm to learn about Insulin and its Metabolic Effects.

GI has a weakness because adding fats and some proteins to high-GI foods lowers the GI but can increase the insulin response. Saturated fats, monounsaturates and omega-6 polyunsaturates raise the insulin response to carbs.

There is another index called the Insulin Index (II). See http://www.mendosa.com/insulin_index.htm.
The II contains a few surprises. Some proteins (e.g. the whey in milk & yoghurt) produce a large insulin response. As over-secretion of insulin can cause low blood glucose which causes severe hunger pangs, it's not something that someone who wants to lose body-fat really wants. Therefore,the consumption of foods with an II greater than 60 should be minimised for optimum fat loss. So take it easy with the baked beans ("my carbohydrates are exceedingly complex"). Overcooking foods raises their GI & II and baked beans are well-overcooked in a sugary sauce. EDIT: I now know that insulinogenic proteins are also glucogenic, so there is no low blood glucose.

On the other hand, refrigerating some foods lowers their GI & II by changing the starch in them into resistant starch, even if the food is subsequently re-heated. Rice & potatoes are two such foods.

As the terms "simple" and "complex" are meaningless in terms of carbohydrates' effects in the body, I prefer to use the terms "slow" and "fast". In a nutshell, slow carbs are good and fast carbs are bad. These terms can be applied to proteins, too. Egg is slow and whey is fast. Sticking to mostly slow foods keeps blood glucose and insulin levels stable, which results in better appetite control and better health, too.

It was soaring serum insulin levels that were sending me to sleep after carby meals years ago. Postprandial hyperinsulinaemia results in amino acids being shuttled into cells. However, L-tryptophan isn't shuttled into cells, so the level of this amino acid in the blood rises relative to others. As L-tryptophan competes with other amino acids to cross the blood-brain barrier, now that the competition has been removed, more L-tryptophan enters the brain. It's converted into 5-hydroxytryptophan (5-HTP), then serotonin & melatonin. High melatonin levels in the brain cause sleepiness.

So remember, "Right carbs, right amounts, right times."