Food myths

[SkepticLance]

There are lots of widely held beliefs out there about food and health, and a lot have been shown to be incorrect with modern science. here are a couple.

 

1. Salt.

Salt causes high blood pressure - right? Actually only right for a third of the people. There is a gene, common in people of African descent, that causes humans to conserve sodium. This means that with salty food, salt builds up in the body and causes high blood pressure. For the majority of us, that does not happen, and salt is not a cause of high blood pressure. How to tell? Easy. Measure your resting blood pressure. Wait 30 minutes. Eat a teaspoon of salt and wait 15 minutes. Measure it again. If you got the nasty gene, you will see a sizeable jump in blood pressure.

 

2. Potatoes are fattening.

Actually, a medium size potato contributes only 100 calories. A young active male will need 3000 calories per day to maintain weight. That is 30 potatoes per day. Of course, if your potatoes arrive coated with fat, this logic goes down the gurgler.

 

Any other myths?

[DrP]

Spinach was always believed to contain huge amounts of iron compared to other vegetables - thus the whole thing about Popeye and his strength. Apparently this is a myth due to an error by people who done early studies on the iron content in foods - a slip of one decimal place in the publication made people believe it was 10 times richer in iron than it was.

[Dudde]

Homecooked meals are better for you.

 

Not that I don't believe this sometimes - but you gotta see some people cook!!

[ydoaPs]

 

2. Potatoes are fattening.

Actually, a medium size potato contributes only 100 calories. A young active male will need 3000 calories per day to maintain weight. That is 30 potatoes per day. Of course, if your potatoes arrive coated with fat, this logic goes down the gurgler.

 

Calories aren't necessarily as important as blood chemistry. While a medium potato may only have 100 Calories(I assume you meant Calories instead of calories due to the sheer ridiculous nature of the claim otherwise) it is mostly starch. Starches are like tiny sugar grenades and release the sugar into the bloodstream very quickly. Potatoes are very high on the glycemic index and are thus fattening.

[SkepticLance]

To yourdad

 

Yes, I meant Calories (or kilocalories). Sorry for the confusion.

According to the article I read recently, there are several different types of starch in potatoes, and some are almost indigestible - providing the equivalent of fibre rather than starch. Hence the lower number of Calories than previously understood.

 

Here's what wiki says http://en.wikipedia.org/wiki/Potato

 

"Nutritionally, potatoes are best known for their carbohydrate content (approximately 26 grams in a medium potato). The predominant form of this carbohydrate is starch. A small but significant portion of this starch is resistant to digestion by enzymes in the stomach and small intestine, and so reaches the large intestine essentially intact. This resistant starch is considered to have similar physiological effects and health benefits as fiber: it provides bulk, offers protection against colon cancer, improves glucose tolerance and insulin sensitivity, lowers plasma cholesterol and triglyceride concentrations, increases satiety, and possibly even reduces fat storage (Cummings et al. 1996; Hylla et al 1998; Raban et al. 1994). The amount of resistant starch in potatoes depends much on preparation methods. Cooking and then cooling potatoes significantly increases resistant starch. For example, cooked potato starch contains about 7% resistant starch, which increases to about 13% upon cooling (Englyst et al. 1992)."

[big314mp]

The importance of the glycemic index is more of how fast your body can "use up" the consumed calories. Potatoes aren't fattening because of a high glycemic index. The high GI means that your body will feel hungrier sooner after eating a potato, rather than something with a low GI. The end result being that you eat more.

 

Gaining and losing weight is easily summarized into whether you eat more calories than you burn, or vice versa.

[SkepticLance]

To big31

What you say is true. However, the reason nutritionists are taking another look at potatoes is that they now realise that the indigestible starch component acts as a kind of dietary fibre. Fibre associated with starch foods acts to lower the GI. The fibre equivalent in potato means it has an effective GI that is much lower than previously realised.

 

The result is that potatoes are filling - both at the time of eating, and for some time after. You simply do not feel hungry for quite some time.

 

The fad diet industry is starting to get hold of this idea. You may wish to read :

http://www.associatedcontent.com/article/910247/the_potato_diet_lose_weight_by_eating.html

 

If you need to experience it for yourself, compare a small hamburger with 500 Calories with 5 medium size potatoes (500 Calories). Eat one for breakfast one day, and see how full you feel, and time how long till you are again hungry. Compare it to the other for breakfast another day.

 

I have been puzzled for a long time by the statements that potatoes were fattening (and I do understand the GI argument). The reason for my puzzlement is that about 25 years ago, I read a report on a diet experiment. The researchers took a bunch of people wanting to lose weight, and randomely divided them into two groups. One group was required to eat a pound of potatoes per day, in addition to whatever other foods they chose, and the other group just to continue eating their normal diet. On average, the potato group lost weight while the other gained.

 

Recent reports suggests that nutritionists are again realising that potatoes are not fattening.

 

This is the international year of the potato (no kidding) which recognises its value as a food.

Check http://www.coloradopotato.org/colorado_potato_facts_nutrition.php

[Dudde]

As having come from the state that grows the biggest and best potatos in the U.S (in my opinion, we do export the most - and if anyone says idaho I'll break you in half!) I used to have a diet extraordinarily high in potatoes, and I can tell you that I'm leaning to agree with Skeptic here.

 

Eating potatoes prepared in the right manner (which means with skin) will leave you full for quite some time and is pretty good for you - if you boil them, it's always a good idea to rinse them in cold water for a few seconds. People that PEEL their potatoes may have a different outcome however, as you're losing a whole lot by doing that.

 

it's totally sweet that I can log into scienceforums at work on a sunday>

[big314mp]

lol...TBH, I don't eat enough potatoes to know the slightest thing about their nutritional value/fillingness. I just assumed they were based on the thread

 

Thanks for the info guys!

[SkepticLance]

Here is another query to throw at you guys.

 

Vitamins and anti-oxidants.

We know that vitamins are necessary for good health, and we know that they work on the basis of 'enough is enough'. Vitamin C, for example, is needed by the average person at 50 mg per day. If you ingest 51 mg, the extra is just excreted.

 

But what about anti-oxidants? Tomatoes contain lycopenes, that are supposed to be protective against prostate cancer. Does anyone have evidence of a similar rule, showing enough is enough? Is there an optimum amount, with excess either harmful or just excreted?

[big314mp]

Food Myth that I saw today:

 

MSG really isn't that evil, seeing as "MSG-free" is great marketing tool, whereas the FDA classifies MSG in it's "Generally Recognized as Safe" category.

[Sayonara]

We know that vitamins are necessary for good health, and we know that they work on the basis of 'enough is enough'. Vitamin C, for example, is needed by the average person at 50 mg per day. If you ingest 51 mg, the extra is just excreted.

Just to be absolutely clear on this, it is only excess dosages of the water-soluble vitamins which are harmlessly flushed from the body. Fat-soluble vitamins such as vitamins A and D can accumulate in the body if taken excessively, with toxic results.

[John Cuthber]

Another myth is that glutamate is some "artificial additive" It might be added to some things but, for example, some cheeses are over 1% glutamate. If you think cheese is artificial , tomato juice is about 0.3% glutamate.

 

My other pet hate is the idea that food additives are bad- in many cases, like MSG, they are natural components of other foods. Not just that, but if the improve the keeping properties of the food they may well be reducif exposure to things like aflatoxin.

[big314mp]

Myth: Lactose Intolerance is a food allergy.

 

Fact: Allergies are an immune response, whereas lactose intolerance is not having the enzyme for breaking down lactose.

[Sayonara]

My other pet hate is the idea that food additives are bad- in many cases, like MSG, they are natural components of other foods.

 

Not entirely accurate. MSG is manufactured and added to food products. "Glutamate" is the carboxylate anion of glutamic acid, and while it's true that this is one of the products of MSG dissolving in water, there are other sources of glutamate, which is where the confusion arises. MSG is a sodium salt of glutamic acid, produced by fermentation of carbohydrate sources.

 

To summarise MSG specifically is not found "naturally occurring" in food products, but glutamate (or glutamic acid) is.

 

The idea of MSG being "bad" does not come just from the fact that it's an additive, but from a strange public resistance to the results of various studies linked to the MSG Controversy.

[insane_alien]

i can't stand the myth that ALL e-numbers are bad for you. everything you could possibly put in food(whethere its edible or not) has to have an e-number by law.

 

for example, E-948 is oxygen. if you ask someone 'do you think people should cut out their intake of E-948?' they will probably say 'yes, of course'.

[SkepticLance]

insane alien speak with tongue most sensible.

 

I get miffed about all those food faddists who claim that food preservatives are all so toxic they are causing us to develop cancer etc, in spite of the toxicology studies showing the contrary.

 

What would you prefer? Sausage with an aproved and safe preservative, or sausage with the toxin produced by the botulinum bacteria? Here is a clue. Botulinum toxin is the most toxic substance ever discovered. About a thousand times more toxic than the worst of the dioxins.

[insane_alien]

Botulinum toxin is the most toxic substance ever discovered. About a thousand times more toxic than the worst of the dioxins.

 

true but it doesn't stop people getting it injected into their faces making themselves look quite laughable especially when they try to display emotion.

 

although, botox has been found to have some theraputic uses, but its only actually useful in certain unfortunate circumstances ( a lot more unfortunate than a few wrinkles)

[John Cuthber]

Not entirely accurate. MSG is manufactured and added to food products. "Glutamate" is the carboxylate anion of glutamic acid, and while it's true that this is one of the products of MSG dissolving in water, there are other sources of glutamate, which is where the confusion arises. MSG is a sodium salt of glutamic acid, produced by fermentation of carbohydrate sources.

 

To summarise MSG specifically is not found "naturally occurring" in food products, but glutamate (or glutamic acid) is.

 

The idea of MSG being "bad" does not come just from the fact that it's an additive, but from a strange public resistance to the results of various studies linked to the MSG Controversy.

 

It's not the sodium that gets the blame, its the glutamate. If it were ammonium or potassium glutamate the effect would be very much the same.

 

If someone is affected by MSG they would be ill advised to eat parmesan cheese or soy sauce because the glutamate would get them without worrying what counter ion it had once had.

 

For this assertion "MSG specifically is not found "naturally occurring" in food " to be true there would need to be some mechanism in food that prevented ion pair formation. Is there one?

 

Incidentally, not everything that gets added to food has an E number. Only the things that have been tested and found to be "safe" (whatever that may mean) get E numbers.

[insane_alien]

how about E240(formaldehyde), E519(Copper(II) Sulphate) and E295(Chlorine).

 

hardly 'safe' chemicals. and thats just scrolling through the list ( http://en.wikipedia.org/wiki/E_number)

 

you don't have to go far through it to find ones that are banned for carcinogenicity or something.

[SkepticLance]

There are an awful lot of materials in food of 'natural' origin which are not restricted, for the simple reason that you cannot stop them occurring. For example : we have all been taught to cut out any green in potatoes. That is because the green area (chlorophyll) also contains a natural insecticide - an alkaloid toxin - that can make people sick and even kill them. There was a case in the 1970's when a new strain of potatoes was bred, and a researcher cooked some of them for his meal, and died. That particular strain happened to have excess amounts of this poison.

 

Anyway, here is another food myth. That legally permitted sprays cause food to become harmful. In fact, the opposite is frequently true. If an insecticide spray is used according to directions, the final residual amount of insecticide in food will be one part per million by weight or less. This amount for modern sprays is quite harmless.

 

The insecticide, though, can prevent insects transferring plant diseases that can harm humans. In maize, for example, there is a fungal disease spread by insects caused by the Fusarium fungus, which causes a build up of a fungal toxin, fumonisin. This can lead to a human fetus developing abnormally with neural tube defects. One such is anencephaly - being born with no forebrain. And the incidence of this is much higher among people of Mexican descent who traditionally grow their own, unsprayed maize.

[Sayonara]

It's not the sodium that gets the blame, its the glutamate. If it were ammonium or potassium glutamate the effect would be very much the same.

Not in dispute from me.

 

For this assertion "MSG specifically is not found "naturally occurring" in food " to be true there would need to be some mechanism in food that prevented ion pair formation. Is there one?

That is a false requirement. MSG - along with the millions of compounds which you might claim can occur naturally in food by ion pair formation - does not form spontaneously in food products. It is produced by a very specific kind of fermentation, mediated by bacteria which are normally only found in soil and on human skin.

[Dudde]

how about E240(formaldehyde), E519(Copper(II) Sulphate) and E295(Chlorine).

 

I actually accidentally got a bit of formaldehyde in my mouth one time, it was kinda lemony - or that might've been the candy, I don't know.

[John Cuthber]

If I put my mind to it I could extract MSG from cheese. Probably the easiest way would be to leach it with water then extract the Na and the glutamate by ion chromatography- then recombine them.

[xnebulalordx676]

Well thanks for I was not aware of this. I still hate glutamate though. Has a noticeable taste. Does give migraines. (Thank god I despise little things named most cheese and the tomato.) Thanks for the food facts.

Another myth is that glutamate is some "artificial additive" It might be added to some things but, for example, some cheeses are over 1% glutamate. If you think cheese is artificial , tomato juice is about 0.3% glutamate.

 

My other pet hate is the idea that food additives are bad- in many cases, like MSG, they are natural components of other foods. Not just that, but if the improve the keeping properties of the food they may well be reducif exposure to things like aflatoxin.

 

Man alive that lactose intolerance labeled as a food allergy gets me riled. So many cultures Asian and African had not ever bothered to eat milk and have fine fit body.

I do fine and have had great teeth and bones without milk. I will simply ignore the "you must be allergic" if you cant eat this" label.

Myth: Lactose Intolerance is a food allergy.

 

Fact: Allergies are an immune response, whereas lactose intolerance is not having the enzyme for breaking down lactose.