NAS vs. EFSA: Why Do the Reference Values Differ?

In our nutrition calculator, you can switch between two reference systems — NAS (USA) and EFSA (EU). For most nutrients, the values are similar, but for some they diverge noticeably. Here's why.

What is NAS?

The National Academies of Sciences, Engineering, and Medicine (NAS) is an independent US scientific organization. Its nutrition board sets the Dietary Reference Intakes (DRI) — the official nutrient reference values used as a basis in the US and referenced widely elsewhere.

What is EFSA?

The European Food Safety Authority (EFSA) is the European Union's food safety agency. It sets the Dietary Reference Values (DRV) — the European counterpart to the DRIs, with its own scientific methodology and, at times, its own conclusions.

Why do the values differ?

Both bodies review much of the same scientific literature but don't always reach the same conclusions — partly because they make different bioavailability assumptions, weigh study populations differently, or use different methodological approaches to risk assessment. For some nutrients this results in barely any difference; for others, the numbers diverge quite a bit.

Concrete examples

The biggest outlier is omega-6: NAS sets a considerably higher value than EFSA. For saturated fat, EFSA doesn't give a fixed percentage at all — just the guidance "as low as possible" — while NAS sets a clear 10% ceiling. For chromium, EFSA deliberately hasn't set a value, since it didn't consider the evidence sufficient — in that case, our calculator automatically shows you the other source's value instead, with a short note explaining why.

Which system should I use?

• Live in the US or reference US sources (e.g. food labels with %DV)? → NAS
• Live in the EU or elsewhere in Europe? → EFSA usually aligns better with local dietary guidance.
• Both systems are scientifically grounded — there's no "right" or "wrong" here, just different approaches to the same question.