Grains and Bread

TL;DR. Three grasses (wheat, rice, maize) supply roughly half the calories humanity eats. A whole grain is three parts: bran, germ, and endosperm. Refining removes the first two, which takes almost all of the fibre, most of the B vitamins, most of the minerals, and all of the fat, leaving mostly starch. Whole grain intake is associated with lower mortality about as consistently as anything in nutrition. But "wholemeal" on a label does not tell you the particle size, and finely milled wholemeal flour behaves in your blood much like white. Coeliac disease affects about 1 percent of people and is a serious autoimmune condition; gluten avoidance without it has no demonstrated benefit.

1. What a grain is

A caryopsis: a dry, one-seeded fruit where the seed coat is fused to the fruit wall. Grains are the seeds of grasses (family Poaceae), except the pseudocereals, which are unrelated plants used the same way.

Buckwheat is not wheat and contains no gluten; it is related to rhubarb and sorrel.

The three parts

Refining removes bran and germ. The reason is not conspiracy: the germ contains oil, oil goes rancid, and refined flour keeps for a year while wholemeal keeps for a few months. White flour also produces lighter bread and was historically a luxury. The nutritional cost is large: refining removes roughly 80 percent of the fibre, 60 to 80 percent of most B vitamins and minerals, and essentially all the vitamin E. Fortification puts back a few (iron, thiamine, niacin, riboflavin, and in many countries folic acid) and does not put back fibre, magnesium, vitamin E, or the phytochemicals.

2. What is inside them

Per 100 g cooked:

Per 100 g of bread: wholemeal about 250 kcal, 7 g fibre, 13 g protein; white about 265 kcal, 2.7 g fibre, 9 g protein. Both are usually 1.0 to 1.3 g of salt per 100 g, which makes bread the single largest source of dietary sodium in many countries, not because it is salty but because of how much is eaten.

Quinoa is genuinely distinctive: a complete protein with good lysine (unusual for a cereal-like food), higher magnesium, and gluten-free. Its saponin coating is bitter and must be rinsed off; most commercial quinoa is pre-washed.

Oats contain beta-glucan, a viscous soluble fibre with one of the few health claims authorised in both the EU and US: 3 g a day lowers LDL cholesterol by roughly 5 to 10 percent.

3. Whole grain: what the evidence shows

Strong and consistent. The 2016 BMJ dose-response meta-analysis by Aune and colleagues, covering 45 studies, found that each 90 g daily increment of whole grains was associated with roughly:

• 19 percent lower coronary heart disease
• 12 percent lower stroke
• 22 percent lower cardiovascular disease
• 15 percent lower total cancer
• 17 percent lower all-cause mortality

with benefit continuing to around 210 to 225 g a day. The 2019 Lancet fibre review found the same pattern. This is observational, and it is among the most reproducible associations in nutrition, supported by trials on intermediate markers (blood pressure, LDL, insulin sensitivity) and a plausible mechanism through fibre, magnesium, and phenolics.

The catch is what counts as whole grain. Legal definitions require that the three parts are present in their original proportions. They say nothing about particle size, and particle size governs the glycaemic response:

• Intact or cracked grains (whole wheat berries, bulgur, steel-cut oats, brown rice, barley) digest slowly, because the cell walls are intact.
• Finely milled wholemeal flour has the fibre but not the structure. Wholemeal bread made from fine flour has a glycaemic index close to white bread, around 70 (Chapter 11).

So the practical hierarchy is: intact grains > coarse/stone-ground products > fine wholemeal flour > white flour. A label saying "wholemeal" gets you to the third tier, not the first.

4. Bread, and what fermentation does

Bread is flour, water, salt, and a leavening agent, and the interesting variable is time.

Commercial fast bread (the Chorleywood Bread Process, developed in 1961 and dominant in the UK and elsewhere) uses intense mechanical mixing, high yeast levels, oxidising agents, fat, and enzymes to make a loaf in about three and a half hours from flour to shelf. It is cheap, consistent, soft, and uses lower-protein domestic wheat. It has essentially no fermentation time.

Genuine sourdough ferments for 12 to 48 hours with a culture of wild yeasts and lactic acid bacteria. Measurable consequences:

• Phytate is largely degraded (50 to 90 percent) by the acidic conditions activating the flour's own phytase, so iron, zinc, and magnesium absorption improves substantially (Chapter 18).
• Lower glycaemic response, by roughly 20 to 30 percent versus fast-fermented bread, partly from the organic acids slowing gastric emptying and starch digestion.
• Partial gluten breakdown, though not enough to make it safe for coeliac disease.
• FODMAP reduction: long fermentation degrades fructans substantially, which is why some people who react to standard bread tolerate long-fermented sourdough. This is a real, measured effect and it is probably the explanation for a good share of self-diagnosed "gluten sensitivity."
• Better keeping, from the acidity.

"Sourdough" is not a protected term in most countries. Much supermarket sourdough is yeast-raised bread with added acid or a small amount of starter, made fast, sometimes called "sourfaux." Look for a short ingredients list: flour, water, salt, and starter, with no commercial yeast, no vinegar, and no improvers.

5. Gluten, coeliac disease, and everything else

Gluten is the network formed when two wheat proteins, gliadin and glutenin, hydrate and are worked. It is what makes dough elastic and traps gas, and it is the reason bread exists as we know it.

Four distinct situations get conflated:

1. Coeliac disease. An autoimmune condition affecting roughly 1 percent of people, in which gluten triggers an immune attack on the small intestine that flattens the villi and causes malabsorption. Consequences include anaemia, osteoporosis, infertility, neurological problems, and increased lymphoma risk. It is diagnosed by serology (tTG-IgA) and duodenal biopsy, and you must still be eating gluten for the tests to work, which is why self-imposed gluten avoidance before testing is a genuine clinical problem. Treatment is complete lifelong gluten avoidance, including trace contamination. It is not a preference.

2. Wheat allergy. A true IgE-mediated allergy, distinct from coeliac disease, with immediate symptoms.

3. Non-coeliac gluten sensitivity. Real symptoms, contested cause. The key evidence: several double-blind crossover trials, notably by Biesiekierski and colleagues, found that people who reported gluten sensitivity did not reliably react to gluten when it was blinded, and did improve on a low-FODMAP diet. The fructans in wheat, not the gluten, appear to explain a large share of cases. This matters practically, because fructan reduction (long-fermented sourdough, smaller portions, spelt in some cases) is easier than total gluten avoidance.

4. Choosing to avoid gluten without any of the above. There is no demonstrated benefit. Gluten-free processed products are typically higher in sugar, fat, and salt, lower in fibre and B vitamins, more expensive, and frequently not fortified. Cohort data associate low gluten intake in people without coeliac disease with lower whole grain intake and no cardiovascular benefit.

Dermatitis herpetiformis is the skin manifestation of coeliac disease: an intensely itchy blistering rash, often on elbows, knees, and buttocks, which responds to a gluten-free diet.

6. Rice: arsenic and the practical response

Rice takes up inorganic arsenic from soil and water far more than other crops, because paddy flooding chemically mobilises it. Inorganic arsenic is a Group 1 carcinogen.

The facts that matter:

• Brown rice contains more than white, because arsenic concentrates in the bran. This is one of the few cases where refining reduces a harm.
• Origin matters enormously. Rice from parts of the southern US (grown on former cotton land with arsenical pesticide history), and from Bangladesh and parts of India, tends to be higher. Basmati from India and Pakistan and rice from California and parts of Europe tend to be lower.
• Cooking method matters. Cooking rice in a large excess of water (6 to 10 parts water to 1 part rice) and draining removes 40 to 60 percent of the arsenic. Parboiling and draining before cooking removes more. Soaking overnight and rinsing helps.
• Babies and young children are the priority group, because intake per kilogram of body weight is high. UK and US guidance advises against rice drinks as a milk substitute for under-fives, and varying the grains in infant cereals.

The reasonable position: rice is fine as part of a varied diet, vary your grains, cook it in plenty of water and drain, and take the infant guidance seriously.

7. Practical guidance

• Prefer intact grains where you can: bulgur, barley, farro, whole oats, brown or wild rice, freekeh, buckwheat, quinoa. They cook in 20 to 45 minutes and reheat well.
• Batch cook and freeze. The main barrier is time, and it is solvable once a week.
• Cook and cool starchy grains for resistant starch; next-day rice and pasta salad give lower glucose responses (Chapter 11). Cool cooked rice fast and refrigerate within an hour, because Bacillus cereus spores survive cooking and germinate at room temperature.
• Cook pasta al dente. Overcooked pasta has a substantially higher glycaemic index.
• Read bread labels. "Wheat flour" means white. "Wholemeal" or "whole wheat" should be first on the list. "Multigrain," "granary," "brown," "wheatgerm," and "stoneground" do not guarantee whole grain, and caramel colouring makes white bread brown.
• Oats for cholesterol: 3 g of beta-glucan a day, roughly 70 to 80 g of oats.
• Salt in bread is worth noticing: it is the largest single sodium contributor in many diets.
• Store wholemeal flour in the fridge or freezer. The germ oil goes rancid in a few months at room temperature.

8. The bottom line

• A whole grain is bran, germ, and endosperm. Refining removes the first two and with them most of the fibre, minerals, vitamin E, and phytochemicals; fortification restores only a few.
• Whole grain intake is associated with lower mortality about as consistently as anything in nutrition, with benefit continuing to around 200 g a day.
• Particle size matters as much as the label. Finely milled wholemeal behaves much like white in your blood; intact and cracked grains do not.
• Long fermentation is the underrated variable: genuine sourdough degrades most of the phytate and much of the fructan content, lowers the glycaemic response, and does not make bread safe for coeliac disease.
• Coeliac disease affects about 1 percent of people, is autoimmune and serious, and requires testing before removing gluten. Most self-reported gluten sensitivity appears in blinded trials to be a fructan problem.
• Rice concentrates inorganic arsenic. Vary your grains, cook rice in excess water and drain, and follow the infant guidance.

Sources and notes

Composition figures are from USDA FoodData Central. Grain anatomy and the losses on refining follow standard cereal chemistry texts and the Whole Grains Council definitions. Whole grain intake and mortality is Aune et al., BMJ, 2016, covering 45 studies, and Reynolds et al., The Lancet, 2019. Particle size and glycaemic response follow Jenkins' and Wolever's work and Juntunen et al.'s comparisons of wholemeal flour with intact kernels. The Chorleywood Bread Process is documented by the Campden BRI and in Ashton's Bread Matters. Sourdough fermentation and phytate degradation follow Lopez et al. and Nionelli and Rizzello's reviews; the glycaemic effect follows De Angelis et al. FODMAP reduction by long fermentation follows Ziegler et al., PLoS ONE, 2016. Coeliac disease prevalence, serology, and the requirement to be eating gluten before testing follow NICE guideline NG20 and the ACG guideline. Non-coeliac gluten sensitivity blinded rechallenge is Biesiekierski et al., Gastroenterology, 2013. Oat beta-glucan health claims follow EFSA and FDA authorisations. Rice arsenic, cooking-method reduction, and infant guidance follow the FSA, EFSA's 2009 and 2014 opinions, and Meharg's work at Queen's Belfast.

Open questions. How much of the whole-grain benefit is fibre, how much is the intact structure, and how much is what whole grains displace has not been separated. Whether non-coeliac gluten sensitivity exists as a distinct entity at all remains genuinely disputed.

👉 Next: nuts and seeds.