Facts about Sugar (2)

Came across this video through the Daily Lipid regarding fructose.



In my previous blog, I indicated that sugar is bad for us because we ate too much (which leads to fatty acid and triglyceride synthesis) and because refined sugar is empty calorie.

It is still true that excessive sugar is bad for us as when our body have too much of any one of the three dietary monosaccharides (glucose, fructose & galactose), fatty acids and triglycerides will be synthesized. Fatty acids get stored and make us look fat. Too much triglyceride is a risk factor for cardiovascular disease.

However, according to Dr. Robert Lustig, fructose is simply toxic. While glucose can be metabolized by every cell in the body, fructose can only be metabolized in the liver. Therefore, in this regard, consuming high fructose is like consuming high alcohol, which damages liver. And the byproducts of fructose metabolism are toxic, one being uric acid, the agent in gout. Galactose (mostly found in milk) is also metabolized in the liver, but we usually do not consume excessive amount.

So I stand corrected. Not all sugar is created equal. On the other hand, it is probably too radical to label fructose toxic. If eating whole fruits is healthy, then fructose cannot be toxic.

Why too much sugar is bad for us?

It seems that every one agrees that too much sugar is bad for us. However, nobody agrees how much is too much and why?

First of all, sugars are empty calories.

Secondly, we are not the only ones who like sugar. Some bacteria inhabiting our body but harmful to us seem to like sugar as well.

We all know the sugar causes tooth decay. After eating sugar, sticky glycol-proteins start to adhere to the teeth. At the same time, millions of bacteria known as Streptococcus mutans also adhere to the glycoprotein. In the next stage, the bacteria use the fructose in a metabolism process of glycolysis for energy. The end product of glycolysis under anaerobic conditions is lactic acid. The lactic acid creates extra acidity to decrease the pH to the extent of dissolving the calcium phosphate in the tooth enamel leading to the start of a cavity. That’s what sugar does to our teeth.

Helicobacter pylori, the bacteria that cause a chronic low-level inflammation of the stomach lining and are strongly linked to the development of duodenal and gastric ulcers and stomach cancer, seem to love glucose as well (see here).

Most importantly, sugar (which includes simple sugar, disaccharide and refined starch) raises the blood glucose level rapidly, which in turn triggers the release of insulin. Too much sugar intake means rapid fluctuations of blood sugar level, which is not healthy because of the stress they place on the body.

In addition our overall wellness and longevity seem to be closely connected to insulin signaling pathway. Metformin, a drug to treat type 2 diabetes, seems to show promise as a calorie restriction mimetic in the worm C. elegans (see here).

Now we have established that too much sugar is bad for us. How much is too much? I have already cut out processed mono- and disaccharides in my diet. If the sugar you eat comes from whole foods (fruits, vegetables and grains), can you still eat too much sugar (carbohydrates)? The answer is yes and very controversial. There exist two camps on the nutrition frontiers, one promotes low carb and another promotes low fats. There is practically no agreement between the two.

In the end, I decided to calculate backwards in order to find out how much carb. I should eat. I set my daily caloric intake at 1600. My protein intake I decided is 46 gram (1 g per kg of body weight) daily. My fat intake I set at 50 gram.

Fat 50g x 9 = 450 calorie ÷ 1600 = 28%
Protein 46g x 4 = 184 calorie ÷ 1600 = 12%

Therefore, my carbohydrates intake is 100% - 12% -28% = 60%
60% x 1600 = 966 calorie ÷ 4 = 242 gram of carbohydrates daily.

Of course, the ratios are there only as a goal to strive for. In reality, the total amount of calorie intakes varies from 1400 to 1800 a day. Fat intake varies from 20 to 35%, protein from 10 to 20% and carb from 45 to 60%.

Of the above numbers, most nutritionists will agree to the amount of protein I intake.

For the low fat camp, 50g of fat or 28% of total calorie is way too much. As for the low carb camp 242g of carb. or 60% of total calorie is a horror story.

However, growing up in a starving China, and having seen many women lived past 90 on mostly carb diet, it is very difficult for me to accept that high fat diet is healthy. In addition, how do you eat only the fat part without taking in too much protein? In addition, a lot of goodies such as fibers, vitamins and anti-inflammatory phyto-chemicals are associated with carbohydrates.

So I will eat carb, be it rice, pasta, bread, vegetables or fruits as long as non of them contains added sugar or vegetable oils.

Facts about Sugar

1. What Are Sugars

The followings are most commonly known sugars:

Glucose (dextrose): a simple sugar (monosaccharide)
Fructose: a simple sugar (monosaccharide)
Galactose: a simple sugar (monosaccharide)

Sucrose (saccharose): a disaccharide with glucose and fructose
Maltose: a disaccharide with two unit of glucose
Lactose: a disaccharide with galactose and glucose, mostly found in dairy products

The followings get turned into sugar (glucose) in our body:

Starch: a polysaccharide with a large number of glucose units joined together by glycosidic bonds. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin.

Maltodextrin: a polysaccharide produced from starch by partial hydrolysis, which will break down to glucose

2. What Are Refined Sugars and What Are Natural Sugars

Sugar belongs to carbohydrates. Carbohydrates are divided into 4 groups, monosaccharides (one simple sugar), disaccharides (2 simple sugars), oligosaccharides (more than 3-9 simple sugars), polysaccarides (more than 10 simple sugars).

Table sugar is a refined sugar; it is sucrose extracted from sugar cane or beet. Brown sugar, raw sugar etc. are all refined sugar.

High fructose corn syrup (HFCS) is a refined sugar; it is 42% fructose and 58% glucose and manufactured from corn.

Manufactured galactose used in commercial bakeries is a refined sugar. It is also used to tone down overly acidic or tart flavors in foods.

Maltose found in high maltose corn syrup (HMCS), also referred to as maltodextrin, is a refined sugar. Maltose can also be made from barley, rice, potato etc.

Honey is almost a natural product and not considered refined sugar, but is mainly fructose (about 38.5%) and glucose (about 31.0%).

Maple syrup is also almost a natural product and not considered refined sugar; it is mainly sucrose and water.

Why do I consider honey and maple syrup almost natural rather than all natural? Because both products sold in the stores pass through some processing methods. The only true natural sugar is the sugar you get by eating whole fruits (fresh or frozen), such as apple, grapes, blue berries etc. Natural sugars also exist in sweet potatoes, corn and peas……

3. Is Sugar Good for You

Obviously, otherwise why would you be given intravenous glucose whenever you are in the hospital?

The reason why sugar gets such a bad rap is partly because we consume way too much (which leads to fatty acid and triglyceride synthesis)and partly because we consume refined sugar (empty calories with no nutrients). The latter is something like buying a pair of pliers from dollar store for a dollar and find out that it is a piece of junk so you throw it away and buy a pair of Stanley for $20.00. I still have my $20.00 pliers after I have used it for 10 years and it will probably last another 10. You can either drink a can of soda loaded with empty calories for $0.25 or getting the equivalent amount of sugar in frozen peas for 10 times the cost. The cheap soda makes you energized right away; and the latter just makes you full. I knew right away the pair of dollar store pliers was not good since it did not do a job required. We still do not know how to communicate with our bodies to find out what types of foods are good for us long term. We rely on scientists to find out. Often nutrition research is done through causality and we all know the chicken or the egg causality dilemma. We all love sugar through no fault of our own (evolution conditioned us to love sugar), and sugar is everywhere and cheap.

Unlike essential amino acids I do not believe that there are any essential sugars, though some claim that there are 8 of them. As studies show that sub-maximal endurance performance can be sustained despite the virtual exclusion of carbohydrate from the human diet ( see here). The only one that comes closest to essential sugar is glucose, but our body can breakdown many carbohydrates into glucose.

4. How to Incorporate Sugar into Your Diet

I try to follow a role model in the family as genetic make-up along with energy needs probably affect how much sugar you need. My maternal grandmother lived till 91 years old in good health. She ate very little and was vegetarian. She sat a lot (doing low vocal Buddhist chanting), so her energy need was little. The sugar she used occasionally was the sugar fellow villagers made from sugar cane. Basically, the sugar was made by boiling the juice squeezed from the sugar cane until majority of the water was evaporated. The sugar we got from the villagers looked like dark brown chocolate truffles. I spent my year 1 to 6 in that village and loved sugar cane season. Farmers set up outdoor cooking pits to boil the juice and all the kids running around eating sugar canes. When it got dark in the evening, we were then given these dark sugar clumps to take home. Now I would call those clumps natural sugar. My grandmother also loved persimmons, both fresh and dried, so she ate them as much as they were available to her. She ate white rice every day and it was her main source of calories. White rice breaks down to glucose.

I think sugar boost on an emergency case is not unhealthy. Unfortunately, most of us think every day life is an emergency. That’s how I thought when I was working. I used to boost myself every two hours with coffee, milk and sugar. Now if I need a sugar boost, I either drink fruit juice without added sugar or take a spoon of honey.

With the exception of occasional honey and fruit juice, all the sugars I eat now are from whole foods. I eat quite a lot of fruits each day. Right now I eat one apple, one cup of grapes and half pint of blue berries. Other sugar related foods I eat are white rice, sweet potatoes, spaghetti and pumpernickel bread. The pumpernickel bread I eat is made in Germany since the North American ones use too many additives.

I would like to eat less quantity in every thing, not just sugar. I am in the processing of training my body to do so. In the meantime, I am taking one day at a time and each day is One Great Day.

How to eat well

The more I look into how to eat well, the less I seem to know. For many years, we have been told to avoid fat, animal fats mostly, such as fatty meat, lard and butter. Then we found out that trans fat is bad for you, so we avoided Margarine. Then it seemed that carbohydrates might have been the culprit that made us fat and caused us to have a whole range of other metabolic related diseases.

We cannot just eat protein for our caloric needs. Fibers are attached to carbs. and essential fatty acids are, well, essential. Another factor complicated protein intake is that studies showed methionine restriction without energy restriction extends lifespan in laboratory animals. Methionine is one of the essential amino acids that we humans cannot make ourselves, but is a must for us.

In the end, I will stick to the diet that I grew up with, which consists of rice, vegetables, fruits, nuts, shellfish and fish.

Two ingredients that I will avoid eating as much as possible, which are:

Refined Sugar (sucrose, glucose, fructose, lactose, maltose, Maltodextrin etc.)
Seed oils (often labeled as vegetable oils, olive oil is the exception)

The American know-how has made these two ingredients wonderfully cheap so they are everywhere in the processed foods. The Mediterranean diet is believed to be healthy. They use animal fat for cooking and olive oil for everything else. While growing up in China during the Cultural Revolution, cooking was done with either lard or peanut oil. Peanut oil (and canola oil) is better than most other seed oil, as they contain less linoleic acid.

When you avoided these two ingredients, you avoided almost all of the processed foods, which unfortunately also include chocolate and bread, the two foods I miss most whenever I go healthy eating.

In the end, I will adhere to eating with moderation.