Free Health Calculators & Tools

USDA FoodData Central reports vitamin A in four separate columns for a reason. Retinol from animal foods is used directly; carotenoids from plant foods convert at roughly 12 to 1. This guide pulls live FDC values for nine common foods and explains RAE versus IU, bioavailability factors, and the toxicity gap between preformed vitamin A and beta-carotene, with citations to NIH ODS, WHO, Harvard, Mayo Clinic, and the IOM.

May 1, 2026 9 min read

Nutrition

Vitamin C Foods Beyond Oranges: USDA FoodData Central Data (2026)

Building HealthSavvyGuide on USDA FoodData Central, I aggregated nutrient profiles for 1,465+ foods. The vitamin C ranking does not match common advice.

Apr 30, 2026 8 min read

Nutrition

Vitamin K1 vs K2: Why USDA FDC Data Reveals a Major Gap in Food Tracking (2026)

Building HealthSavvyGuide on USDA FoodData Central, I noticed K1 (phylloquinone) is well-documented but K2 (menaquinones) appears in only a fraction of food entries. Here is what that gap means and which foods reliably contain each form.

Apr 29, 2026 9 min read

Nutrition

Selenium-Rich Foods, Thyroid Health, and What USDA FDC Data Reveals (2026)

Building HealthSavvyGuide on the USDA FoodData Central API, the selenium dataset surprised me. From Brazil nut variability to fish, eggs, and whole grains — here is what the numbers actually show, with NIH ODS guardrails.

Apr 28, 2026 7 min read

Nutrition

Folate (Vitamin B9): What USDA FoodData Central Data Reveals About America's Most Successful Nutrient Fortification Program

When I started building HealthSavvyGuide on the USDA FoodData Central API, the folate numbers for enriched grains did not add up the way I expected. Here is what the data reveals about America's most successful nutrient fortification program.

Apr 27, 2026 10 min read

Nutrition

Magnesium-Rich Foods and Deficiency Signs: USDA FoodData Central Analysis (2026)

An engineer's read of the USDA FoodData Central database on magnesium content in whole foods, NIH-backed deficiency signs, and the bioavailability gaps single-article lists miss.

Apr 26, 2026 9 min read