Nutrix Lab

Pair 01 Lentils · Bell pepper
Iron · pH

Mərci + bolqar bibəri

Lentils + red bell pepper

Does red bell pepper change how much iron is released from lentils during digestion?

Status
This pairing is in preparation. No measurement from NUTRIX LAB is published on this page yet — everything below is either published research by others, clearly cited, or what this project plans to do.
Placeholder for a photograph of dry green lentils raked flat and weighed.
PLATE 02 — Green lentils (mərci), dry and weighed. Placeholder
Placeholder for a photograph of a red bell pepper cut cheek, seed side up, weighed.
PLATE 03 — Red bell pepper (bolqar bibəri), cut cheek. Same surface and light as Plate 02. Placeholder

§1 Ingredients

Why these two

Lentils carry iron in its non-heme form — the form found in plants, and the form whose uptake is most easily pushed up or down by whatever else is in the same meal. They also contain phytate, a storage compound in pulses and grains that binds minerals and tends to hold iron in place.

Red bell pepper is a notably concentrated source of ascorbic acid (vitamin C). Ascorbic acid is the best-documented dietary enhancer of non-heme iron uptake, and it is also fragile: it degrades with heat and leaches into cooking water.

So the pair sets two known chemistries against each other in a dish people actually eat, and it makes preparation method part of the question rather than a footnote to it.

§2 Method

Preparation to be compared

Each variant is prepared the same way every time it is run, so the only thing changing between them is how the pepper met heat and water. Exact quantities, timings and temperatures are fixed in the written protocol and published with it.

Table scrolls sideways →

Planned preparation variants
Variant Bell pepper Lentils Why it is in the set
A Raw, diced Boiled Ascorbic acid at its highest. The upper bound for any effect.
B Boiled with the lentils Boiled Closest to a cooked dish. Heat and leaching into the water both act.
C Baked, dry heat Boiled Heat without leaching, separating the two losses.
D None Boiled Lentils alone — the reference every variant is compared against.
Placeholder for a photograph of raw, boiled and baked bell pepper in equal portions side by side, photographed from above.
PLATE 04 — Variants A, B and C in equal portions, overhead, one frame. Shot as a set so the three are comparable. Placeholder — photograph needed

§3 Evidence

Evidence

Measured by NUTRIX LAB Our bench

Nothing published here yet for this pairing. When there is, it appears in this block and nowhere else on the page, with the run date, the number of repeats and the raw data alongside it.

Published by others Cited literature — not our data

Ascorbic acid raises non-heme iron absorption in single meals

Human single-meal studies show ascorbic acid increasing non-heme iron absorption, with the effect increasing as the dose rises and working against phytate's inhibition.[1] These were controlled test meals, not lentils with bell pepper.

Over a whole diet, the picture is less clear

When ascorbic acid intake was raised across a complete diet rather than a single test meal, iron absorption did not change significantly.[2] A single-meal enhancement does not automatically carry over to how people eat across a day — one reason this pairing is worth measuring rather than assuming.

Phytate in pulses works in the opposite direction

Reducing phytate in cereal porridges improved iron absorption in human subjects, confirming phytate as a substantial inhibitor of non-heme iron uptake.[3] Lentils contain phytate, so the two chemistries in this pairing pull against each other.

What the digestion model measures

The standardised static in-vitro digestion protocol used in this field produces a bioaccessible fraction — how much is released into solution under controlled conditions.[4] It is a comparison tool between samples, not a measurement of what a person absorbs.

What we plan to measure Planned work
  • Iron bioaccessibility across variants A–D, so the effect of raw, boiled and baked pepper can be separated.
  • pH of the combined matrix before and through simulated digestion.
  • Repeats of each variant, with the number reported alongside the result rather than left implied.

We did not find published work measuring this specific pairing, at household proportions, across these preparation methods. That gap is the reason it is Pair 01.

§4 Limits

What a result here would, and would not, mean

A difference in bioaccessible iron between variants would mean the combination changed how much iron was released under these laboratory conditions. It would be a reason to look further.

It would not mean anyone absorbed more iron, that iron status improved, or that one lunch is healthier than another. Those are claims about people, and they need research on people — with ethical approval, consent and a suitable research partner.

§5 Cost

Cost

Table scrolls sideways →

Per 100 g — to be priced
Ingredient Price (AZN) Shop Date priced
Mərci ———
Bolqar bibəri ———

Prices are collected in shops, photographed, and published with the shop name and the date. Nothing is estimated.

§6 Sources

Sources

  1. Hallberg L, Brune M, Rossander L. Iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate. The American Journal of Clinical Nutrition, 1989.
  2. Cook JD, Reddy MB. Effect of ascorbic acid intake on nonheme-iron absorption from a complete diet. The American Journal of Clinical Nutrition, 2001.
  3. Hurrell RF, Reddy MB, Juillerat MA, Cook JD. Degradation of phytic acid in cereal porridges improves iron absorption by human subjects. The American Journal of Clinical Nutrition, 2003.
  4. Brodkorb A, Egger L, Alminger M, et al. INFOGEST static in vitro simulation of gastrointestinal food digestion. Nature Protocols, 2019.

Volume, page numbers and DOI links are to be added by the project team after checking each reference against the original article.