Sugar and Vitamin/Mineral Absorption

[Jorpho]

It's bloody impossible to try to find accurate nutrition information on the Internet anymore, isn't it?

I heard some talk along these lines today:
http://healthandscience.eu/index.php?op ... Itemid=198

How does sugar skew the body’s vitamin and mineral balance?

The refinement of sugar canes strips them of around 40 vital nutrients, leaving the white sugar with nothing else than empty calories. In our intestinal system, the white sugar is broken down into fructose (that is passed on to the liver) and glucose (that is absorbed quickly in the bloodstream). Glucose is used to produce the energy molecule, ATP. This requires a number of enzyme processes that depend on B vitamins, calcium, magnesium, and other minerals. However, as white sugar is refined, the body must collect vitamins and minerals from other parts of the body. In this connection, our bones serve as the primary “mineral bank”. Consuming sugar, in other words, is like making constant cash withdrawals, and unless we make sure to replace what we take out from our account, we risk going bankrupt, figuratively speaking.

Sugar, soft beverages, and the acid-base balance

If we consume too much sugar, it weakens our bones. Moreover, sugar leads to an acid build-up in the bloodstream, which requires a tightly regulated pH value. Base-forming minerals like calcium and magnesium are dispatched in the blood and subsequently discharged with the urine. Our bones lose calcium, magnesium, and other minerals on that account, and the problem is made worse by consuming soft beverages that contain phosphorus, which belongs to the group of acid-forming minerals.

This sounds all kinds of fishy, but I can't seem to find a good source to refute it properly.

I mean, if nothing else, glucose is surely found in many foods that are a poor source of calcium, is it not? Ergo, consuming any such natural foods ought to be just as calcium-depleting as white sugar, right?

That the body's pH can somehow be swung from "basic" to "acidic" is of course unquestionably hooey, but I confess that I am not so well-read as to discount the possibility that calcium is expended in the natural course of maintaining said pH.

[Pfhorrest]

All of those details sound accurate to what I remember of biology, including the acidification thing; things like lactic acid are a normal byproduct of metabolism, and such acids will form salts with any dissolved bases in the bloodstream (neutralizing them, maintaining the same pH as before), which will be urinated out.

However, that author is unfairly singling out refined sugar in that whole process. Pretty much anything with any caloric value will have the same effects. So the only question is how much calcium (etc) are you getting per calorie you burn. Pure sugar is, of course, high in calories and low in calcium, so a diet of pure sugar would be terrible for you for that reason, as well as lots of others, of course. But that doesn't mean that sugar somehow sucks the calcium out of your bones. It just means it's empty calories, and you need to get your necessary vitamins and minerals elsewhere.

But that's common knowledge and doesn't sound nearly as scary.

[Jorpho]

So, is ATP synthesis from glucose really a major consumer of calcium and magnesium?

[Pfhorrest]

I don't remember that much biology off the top of my head, but looking up the chemical structure of ATP, it appears to be made of only C, H, O, and N, so even if the ATP synthase somehow requires calcium, magnesium, etc, as part of intermediate steps of the reaction (and the Wikipedia article for ATP synthase says nothing about either of those elements), they would have to come out the other end as waste products too, and so would not be "used up", unless there's some other kind of complex biochemistry going on I'm not aware of that e.g. creates salts of them or something.

[jewish_scientist]

Spoiler:

The refinement of sugar canes strips them of around 40 vital nutrients, leaving the white sugar with nothing else than empty calories

I always found the concept of 'empty calories' to be at best misleading and at worse condescending. Foods containing 'empty calories' are simply foods that contain high concentrations of calories and do not contain other nutrients in significant concentrations. However, nothing else is described in this way. No one would describe an orange as having 'empty vitamin C' or a steak as having 'empty vitamin B'.

However, as white sugar is refined, the body must collect vitamins and minerals from other parts of the body.

Am I the only one who finds this sentence particularly odd.

In this connection, our bones serve as the primary “mineral bank”. Consuming sugar, in other words, is like making constant cash withdrawals, and unless we make sure to replace what we take out from our account, we risk going bankrupt, figuratively speaking.

There are 2 types of cells (I forget their names) that work on the calcium in your bones. One constantly breaks the calcium in the bones down and add it back into the bloodstream; the other constantly takes it out of the blood stream and adds it to the bones. The body regulates the amount of calcium in the blood by changing how active these cells are. I think the analogy of a bank is a fairly accurate way to portray this system. However, this system is in no way effected by carbohydrates such as sugar, because the concentration of one in no way changes the concentration of other.*

Moreover, sugar leads to an acid build-up in the bloodstream, which requires a tightly regulated pH value.

Although the pH value of blood falls within a very narrow range, your body is very efficient at regulating it by releasing a molecule (sorry, I forget its name also) that neutralized both acids and bases. In addition, sugar is not acidic or basic, so I see no way for it to change the blood's pH. The only way this sentence makes any sense is if it is referring to anaerobic respiration. If someone exercises so much that the body cannot deliver enough oxygen to the muscles, then the muscles will start to use the carbohydrates in anaerobic respiration, which does produce an acid as a byproduct. However, it is more accurate to ascribe the increase in pH to the exercise, not the carbohydrates.

Base-forming minerals like calcium and magnesium are dispatched in the blood and subsequently discharged with the urine.

This only happens when the body has an excess amount of the nutrient in question. Think about it this way: if the calcium was needed, then your body would not be intentionally removing it.

I mean, if nothing else, glucose is surely found in many foods that are a poor source of calcium, is it not?

One of the most famous calcium rich foods is milk, which also contains a large amount of lipids. All organisms store excess carbohydrates as lipids. Although lipids and carbohydrates are distinct chemicals that need to be viewed as such, they are intimately related to each other.

So, is ATP synthesis from glucose really a major consumer of calcium and magnesium?

The vast majority of the chemicals used in ATP synthesis return to there original form after the process is complete, which is really cool when you think about it.

*In theory, there could be so much carbohydrates in the blood that other components would be displaced, but I am pretty sure your blood would be as thick as syrup by the time that happened.

P.S. If I remember correctly, ATP synthase makes ~2 molecules of ATP per cycle, while the Krebs Cycle and Electron Transport Chain make ~36 per cycle.

[p1t1o]

Here's a good way to refute it:

To be honest, that passage is so full of crap, I wouldnt bother trying to distill science from the rest of the text, its clearly written by someone whose motive was NOT to spread science and knowledge. The passage is a showcase of pseudoscience red flags, mixed in with just the right amount of sciencey words/concepts to seem enticing, but trying to extract nutritional advice from this information is worse than pointless.

There are substances which affect the absorption/excretion/metabolism of various substances but stay a million miles away from whatever source you got this schpiel from.

**edit**
Oh look! If you are worried about any of the concepts written about on their website, they helpfully offer several books for sale on the topic, along with their pet cure-all panacea. Colour me shocked.

Just eat a balanced diet and buy a copy of "Biochemistry" by Stryer et al.

[Jorpho]

To be honest, that passage is so full of crap, I wouldnt bother trying to distill science from the rest of the text, its clearly written by someone whose motive was NOT to spread science and knowledge. The passage is a showcase of pseudoscience red flags, mixed in with just the right amount of sciencey words/concepts to seem enticing, but trying to extract nutritional advice from this information is worse than pointless.

The sad thing is that this is one of the least awful passages of its kind that I could pull up with a little Googling. There are so many pages saying something along those lines that I would have thought they'd be basing it on some distant kernel of truth.

The best I could turn up was a study or two (of uncertain quality) indicating that calcium excretion in urine is elevated following consumption of sugar.

[qetzal]

The reason this is wrong is that Mg and Ca don’t get “used up” during these reactions. They are co-factors for a variety of enzymes, and like the enzymes, they only help catalyze the reactions. They get used for that over and over.

Plus, they are already in every cell of your body. They don’t have to be “collected from other parts of the body.”

Of course, some amounts of Ca and Mg are continually lost in urine, and these do need to be replenished. That doesn’t validate any of the stuff you’ve cited.

[Eebster the Great]

Apart from the details, the basic assumption I have seen in references like these to the evils of refined sugar (sucrose crystals) is that it is metabolized more rapidly than other foods. The basic metric used to measure the rate of metabolism of carbohydrates is the glycemic index, which measures the rate at which plasma glucose concentration increases after consumption. The rate is then normalized so that glucose is 100 (since glucose is the solute ultimately being measured). But the glycemic index of sucrose is not exceptionally high; sources differ, but most put sucrose in the mid 60s, or only about 60-70% of glucose. Baked potatoes, dates, instant rice, white bread, watermelons, and many other foods have a higher GI, some much higher (especially baked potatoes and dates). So if eating table sugar really had the effects claimed here, eating higher GI foods should cause even more severe effects.