Sources
We rely on a small set of authoritative resources for background and on peer-reviewed research for the interactions themselves. This page explains which source we use for what, and why.
Our primary foundation
NIH Office of Dietary Supplements
Used for: nutrient background and established interactions
Part of the U.S. National Institutes of Health, the ODS publishes fact sheets on vitamins, minerals, and dietary supplements covering nutrient functions, food sources, recommended intakes, documented interactions, and safety considerations. Its health-professional fact sheets are referenced and regularly reviewed, which makes them a reliable starting point for what is already well established.
USDA FoodData Central
Used for: food composition and nutrient data
The U.S. Department of Agriculture’s food composition database records what nutrients foods contain and in what amounts. When an article refers to a food as a source of a nutrient, this is where the underlying figures come from. It answers what is in a food — not how much of it a person absorbs, which is the question the Atlas exists to explore.
Dietary Guidelines for Americans
Used for: dietary context and patterns
Issued jointly by the USDA and the U.S. Department of Health and Human Services, the Guidelines describe dietary patterns and population-level guidance. We use them to place an individual interaction in the context of how people actually eat, rather than treating each nutrient as an isolated problem.
PubMed / National Library of Medicine
Used for: the interaction evidence itself
PubMed indexes peer-reviewed biomedical and life-science literature. It is where we find the absorption studies, trials, and reviews that specific interaction claims rest on. PubMed is a discovery database rather than a judgment of quality — being indexed says nothing about whether a study was well designed, which is why the next two sections matter.
Which source answers which question
| Nutrient background | NIH Office of Dietary Supplements |
|---|---|
| Food composition | USDA FoodData Central |
| Interaction evidence | PubMed and peer-reviewed literature |
| Dietary context | Dietary Guidelines for Americans |
| Everything else | Other authoritative government, academic, or professional sources as the topic requires |
How we judge source quality
We do not treat every source as equally authoritative. In rough order of preference:
- Government health and nutrition resources
- Academic institutions and professional organizations
- Systematic reviews and meta-analyses
- High-quality peer-reviewed research
- Relevant primary studies, read in the context of the wider literature
Ranking is a starting point, not a verdict. A well-designed primary study that directly measures the interaction in question can be more informative than a general review that mentions it in passing. We weigh what a source actually measured against the claim we want to make.
Sources we avoid: press releases, single studies reported only in news coverage, supplement-industry material, and any source with a commercial interest in the conclusion.
Transparency rules we hold ourselves to
- A source must support the specific claim it is cited for — not merely be authoritative on the general topic.
- Where credible evidence conflicts, the article explains the disagreement rather than choosing a side quietly.
- Where evidence is limited, the article says so plainly.
- Citations are listed in full so you can read the original and disagree with our reading.
- We do not create an impression of certainty the underlying research does not support.
Citing an organization does not mean it endorses, reviews, or is affiliated with NutriFoodGuide. We reference public resources; those organizations have no involvement with this site.
For how these sources feed into a finished article, see our research and editorial process. If you spot a citation that does not support the claim attached to it, please tell us.
Read the sources in context
Every Atlas article ends with the full reference list behind it.