Carbohydrates and Diet

Introduction

Leading in from my current series of posts on complex carbs...

Over a cup of tea, a friend just said “I need a sugar fix”.  That got me thinking: sugar is addictive.  People are “called” to it as with any other addiction.

The problem is, as with many addictions, the fix is short lived and can cause more problems than it resolves.  Primarily, if the sugar isn't immediately required by the body (ie you’re not exercising), it spikes the insulin response, which causes the body to store sugar in the blood stream in muscles and liver as glycogen, or as fat in the flabby areas around the body (problem 1).  However, whilst eating the sugary food, you do get an immediate and very satisfying mini “high”: sweets called comfort foods for a very good reason.  Sweet.

Following that, the body suddenly finds the initial promise of boundless energy is not sustained: expecting a gradual tail-off of the supply of sugar which can be managed, there’s a sudden drop.  Leading to a down swing in mood and energy – and often a return to hunger.

Glycemic Index

The glycemic index relates to how quickly sugar in foods is absorbed into the blood; it was originally devised to assist diabetics with managing their blood sugar levels by observing how quickly certain foods caused an insulin spike - this insulin spike has been associated with a return to feeling hungry shortly after consuming sweet foods (as I mentioned above).

Some dieters have found that choosing food based on its glycemic index can help them combat hunger pangs and make dieting easier: the bottom line with weight loss is a reduction in calorie intake - obviously, if you're not always ravenously hungry, losing weight is much easier!

Note that the glycemic index of food is an average based on observing how quickly the blood sugar rises after consumption: the numbers you see quoted are therefore not absolutes but only indications of the relative speed of absorption.  For reference, glucose has an average glycemic index of 100, but has been observed to have an index as low as 85 and as high as 111.  Food combinations can also change the glycemic index - consuming glucose with fibre brings the index range down to somewhere between 57-85 - in line with the observation that fibre helps keep you feeling full for longer.

Glycemic Load

The index relates to the rate of absorption into the body, the glycemic load is the product of the number of calories and the glycemic index and is a better indication of the what kind of insulin spike might be caused by consuming food.

There's a table at the end of the article ordered by glycemic load (once -again based on 100g of the food item) predictably, foods with the highest calorific value tend to be towards the top of the table ... however, a normal baked potato moves from near the bottom of the table to the middle and sweet potatoes move from the middle to the bottom!

OK, as I mentioned, everything in the tables has been based on 100g rather than the vague notion of "a portion" ... but practically speaking, what's in a portion?

I have two measures to hand: a baked potato (500g) and a slice of wholegrain bread (50g) ... that means that the glycemic load of the potato is actually 94.9 while two slices of bread is only 69.7 ... the baked potato would therefore be more likely to cause an insulin spike and you'd be more likely to feel hungry later!

Food	Glycaemic Index	Glycaemic Load
Egg Noodles	70	49.7
White Bread	70	37.8
Brown Bread	65	33
Wholegrain Bread	69	69.7
White Rice	60	27
Potato	70	18.9
White Pasta	55	17
Brown Rice	50	11.5
Brown Pasta	39	10.3
Sweet Potato	20	8.2

One of the sources I used to research this was http://www.glycemicindex.com/, some of the values are slightly different: remember, glycemic indexing isn't an exact science

Nutrients in Carbohydrates

Recap

In my post Calories in Carbohydrates, I looked at level, types and quality of the energy that our bodies could get from the various complex carb sources (eg potato, pasta, bread, rice) - always with half an eye on weight management.  This time I'm looking at these essential food sources from the point of view of what kind of nutrients do they have.

So What Have We Got?

Once again there's a table below with all the key complex carbs, this time the table isn't sorted because there isn't any clear way of organizing into a single view.

So I'll start with a fairly well known story about rice and the disease Beriberi (see Wikipedia Beriberi), caused by a deficit of Vitamin B1 (Thiamin) - as the story goes a Dutch doctor in Java found that prisoners eating white rice developed the disease, whereas those fed brown rice did not ... ironically, the table below doesn't bear that out - the reason being that white rice is very often fortified in developed countries to combat that very problem!

Fiber

From the grid, you can pretty easily see that brown/wholegrain foods deliver better on the fiber front than their refined alternatives.  Fiber is primarily used to help digestion, without being digestible itself: it gives the body something to push against and the bacteria in the gut something to feed on.  Getting an adequate quantity of fiber has been demonstrated to reduce the risk of many cancers and heart conditions.

Vitamin A

Vitamin A is necessary for healthy eyes, skin and linings of things like the digestive tracts (among other things); you'll find it as beta-carotene in brightly coloured fruit and veg ... too much can cause horrible things like birth defects, liver disorders and can increase the bone breakdown!  Note that sweet potatoes deliver a massive kick of Vitamin A!

B Vitamins

These are associated with energy production - converting stored sugars, fat and protein into energy to move, think and exist.  they are involved in all the processes that get you moving (eg nervous system, healthy heart, blood production) and the most commonly added to enrich food.  In the table you can see a fairly even distribution of B Vitamins throughout the carb sources, until you get to Folate (Folic Acid); in developed countries Folate is routinely added to grain products (especially flour) as a guard against birth defects.

Vitamin C

Potatoes deliver a healthy punch of Vitamin C, but that's one vitamin that anyone who eats plenty of fruit and veg will get enough of anyway.

Vitamin D

Wasn't measured in the sources I was using, so I can't report of it's quantities.

Vitamin E

Is an important antioxidant and has a key role in nourishing cells; it's rarely added to food, and is naturally higher in the brown and wholegrain foods below.

Vitamin K

Vitamin K is essential for blood clotting (see Discovery of Vitamin K at Wikipedia), but its levels are pretty low in the sources listed below (one mg = 1000 mcg).

Minerals

Generally, unrefined carbohydrate sources have a much higher level of minerals than their refined equivalents (ie wholegrain/brown is better for you than white), but potatoes (both types) deliver one hell of a big punch in the potassium department: it has a key role, along with reduced sodium intake, in reducing and managing blood pressure.  Then compare potatoes' Sodium content with the other sources: it's much, much lower - potatoes, when prepared in a healthy manner (ie not fried, roasted, mashed with butter or made to actually taste like anything) could have a major roll in managing blood pressure!

before I write off other complex carb sources, just take a look at wholegrain bread's phosphorus, magnesium and calcium content.  These three minerals are crucial for bone and teeth development, as well as energy, the nervous system and healthy brain functioning.

Food	RDA - 35 year old 65kg male * approx - no RDA exists	Wholegrain Bread	White Bread	Potato	Sweet Potato	Brown Rice	White Rice	Brown Pasta	White Pasta	Egg Noodles	Brown Bread
Fibre	24* g	7 g	3 g	4 g	7 g	2 g	1 g	4.5 g	1.2g	3 g	6 g
Vitamins
Vitamin A	900.0 mcg	0.0 IU	0.0 IU	10.0 IU	38433 IU	0.0 IU	0.0 IU	4.0 IU	0.0 mg	62.0 IU	3 IU
Thiamin	1.2 mg	0.3 mg	0.4 mcg	0.1 mg	0.2 mg	0.1 mg	0.3 mg	0.2 mg	0.0 mg	0.2 mg	0.3 mg
Riboflavin	1.3 mg	0.1 mg	0.3 mg	0.1 mg	0.2 mg	0.0 mg	0..0 mg	0.1 mg	0.0 mg	0.1 mg	0.2 mg
Niacin	16.0 mg	4.0 mg	3.9 mg	3.1 mg	3.0 mg	1.5 mg	2.3 mg	1.0 mg	0.4 mg	2.1 mg	4.0 mg
Vitamin B6	1.3 mg	0.3 mg	0.1 mg	0.6 mg	0.6 mg	0.1 mg	0.1 mg	0.1 mg	0.0 mg	0.2 mg	0.2 mg
Folate	400 mcg	75.0 mcg	104 mcg	22.0 mcg	12.0 mcg	4.0 mcg	91.6 mcg	7.0 mcg	7.0 mcg	29.0 mcg	65.0 mg
Vitamin B12	2.4 mcg	0.0 mcg	0.0 mcg	0.0 mcg	0.0 mcg	0.0 mcg	0.0 mcg	~	0.0 mcg	0.3 mcg	0.0 mcg
Pantothenic Acid	5.0* mg	0.3 mg	0.3 mg	0.9 mg	1.8 mg	0.3 mg	0.6 mg	0.6 mg	0.1 mg	0.9 mg	0.5 mg
Vitamin C	90.0 mg	0.1 mg	0.0 mg	13.5 mg	39.2 mg	0.0 mg	0.0 mg	0.0 mg	0.0 mg	0.0 mg	0 mg
Vitamin D	5.0* mcg	~	~	~	~	~	~	~	~	~	~
Vitamin E	15.0 mg	0.4 mcg	0.2 mg	0.0 mg	1.4 mg	0.0 mg	0.1 mg	0.4 mg	0.1 mg	0.4 mg	0.8 mg
Vitamin K	120.0* mg	1.4 mcg	3.4 mg	1.7 mcg	4.6 mcg	0.6 mcg	0.0 mcg	1.0 mcg	0.0 mcg	0.5 mcg	9.4 mcg
Minerals
Calcium	1,000.0 mg	103 mg	119 mg	34.0 mg	76.0 mg	10.0 mg	15.8 mg	21.0 mg	7.0 mg	35.0 mg	33.0 mg
Iron	8.0 mg	2.5 mg	3.3 mg	7.0 mg	1.4 mg	0.4 mg	1.9 mg	1.5 mg	1.3 mg	1.9 mg	3.1 mg
Magnesium	420.0 mg	78.0 mg	26.0 mg	43.0 mg	54.0 mg	43.0 mg	19.0 mg	42.0 mg	18.0 mg	58.0 mg	81.0 mg
Phosphorus	700.0 mg	228.0 mg	103 mg	101 mg	108.0 mg	83.0 mg	68.0 mg	125.0 mg	58.0 mg	241.0 mg	187.0 mg
Potassium	4.7* mg	230.0 mg	131 mg	573 mg	950.0 mg	43.0 mg	55.3 mg	62.0 mg	44.0 mg	244.0 mg	314.0 mg
Sodium	1.5* mg	420.0 mg	592 mg	21.0 mg	72.0 mg	5.0 mg	1.6 mg	4.0 mg	1.0 mg	21.0 mg	346.0 mg
Zinc	11.0 mg	1.7 mg	0.7 mg	0.5 mg	0.6 mg	0.6 mg	0.8 mg	1.1 mg	0.5 mg	1.9 mg	1.5 mg
Copper	900.0 mcg	0.3 mg	0.1 mg	0.8 mg	0.3 mg	0.1 mg	0.1 mg	0.2 mg	0.1 mg	0.3 mg	0.3 mg
Manganese	2.3* mg	2.0 mg	0.4 mg	0.6 mg	1.0 mg	0.9 mg	0.7 mg	1.9 mg	0.3 mg	0.9 mg	1.9 mg
Selenium	55.0 mcg	32.9 mcg	31.0 mcg	0.7 mcg	0.4 mcg	9.8 mcg	11.9 mcg	36.3 mcg	26.4 mcg	78.8 mcg	38.6 mcg