Most cards on this page work the same way. Calk adds up a vitamin from recorded food over at least seven complete days and compares the daily average with the EFSA reference for your age and sex. The card appears when food alone reaches that reference and shows the percentage; for a vitamin with an upper level, food and logged supplements together also have to stay below it. Below the reference there is no card at all, since a food missing from the diary would look the same as a food you did not eat. The cards are for adults and pause during pregnancy and breastfeeding. Vitamin C, B12, lutein, spermidine and the fat check follow rules of their own, described in their sections.
The diary cannot measure blood levels, absorption, sunlight exposure or individual medical needs. The Nutrition Report adds another view: on how many days each nutrient had a source.
Vitamin A Sources#
What Calk calculates. Calk combines preformed vitamin A from foods such as liver, eggs and dairy with provitamin A carotenoids from orange and dark-green produce, using retinol activity equivalents NIH 2023.
What you can do. Add a familiar source if the recorded pattern is low. Liver and some supplements contain very high preformed vitamin A; pregnancy and medical context require particular care.
Vitamin C Sources#
What Calk calculates. Vitamin C helps the body absorb iron from plants, so Calk first looks for sittings where the two met: at least 25 mg of vitamin C next to at least 1 mg of iron from legumes, whole grains, nuts, seeds or leafy greens. When that happens on at least two days, the card says the two already come together. Otherwise the usual reference card applies. Peppers, citrus, berries, kiwi, broccoli and potatoes are common sources NIH 2021.
Cooking and storage can change the amount, so the database value is an estimate.
Vitamin D Sources#
What Calk calculates. Calk counts vitamin D in recorded fatty fish, egg yolks, fortified products and some mushrooms NIH 2023.
The food diary cannot see vitamin D made in the skin or interpret a blood test. If vitamin D status is the question, that calls for a blood test and clinical guidance.
Vitamin E Sources#
What Calk calculates. Calk estimates vitamin E from nuts, seeds, plant oils, avocado and leafy greens NIH 2021.
What you can do. Look for a regular food source. Food and high-dose antioxidant supplements are different questions.
Vitamin K Balance#
What Calk calculates. Calk records K1 and K2 separately where the food data has them, and the vitamin-K card itself reads K1, which the food tables cover most completely. K1 is common in leafy greens and other vegetables; K2 occurs in some fermented foods, dairy and animal foods NIH 2021.
Food-composition data for K2 is less complete than for many common vitamins. People taking warfarin or similar medication should follow clinical advice on keeping vitamin K steady, and should not change their vitamin K intake on the basis of an app result.
Vitamin B12 Sources#
What Calk calculates. The reference card works as for the other vitamins. A second card appears when a week of food has no B12 at all, no animal foods and some plant foods: it suggests a B12 source, either fish, dairy or eggs you have eaten before or fortified foods such as plant drinks and breakfast cereals. Unfortified plant foods are not reliable B12 sources NIH 2024.
What you can do. If animal foods are limited, check labels on fortified foods and discuss supplementation when appropriate. Absorption can also be reduced by age, gastrointestinal conditions and some medicines, which the diary cannot determine.
Vitamin B6 Sources#
What Calk calculates. The B6 card follows the rule at the top of the page. Poultry, fish, potatoes, chickpeas, bananas and fortified cereals are common sources NIH 2025.
What you can do. Keep the foods that already supply it. Long-term use of high-dose B6 supplements can damage nerves, so check the dose of any supplement with a doctor.
Thiamin Sources#
What Calk calculates. The reference for thiamin (vitamin B1) depends on energy, so it rises with your calorie target. Whole grains, fortified bread and cereals, pork, fish, legumes and seeds are common sources NIH 2023.
What you can do. Keep the grain and legume dishes that carry it. Regular heavy drinking reduces how much thiamin the body absorbs, and that is a question for a doctor whatever the diary shows.
Folate Sources#
What Calk calculates. Calk uses dietary folate equivalents to combine natural folate from legumes, greens, citrus and other foods with folic acid from fortified foods NIH 2022.
In pregnancy, follow the medical guidance rather than this food estimate. People who could become pregnant may need folic acid in addition to food according to local medical recommendations.
Choline Sources#
What Calk calculates. Calk estimates choline from eggs, meat, fish, dairy, soybeans, legumes and cruciferous vegetables NIH 2022.
What you can do. Add a source that fits the existing diet. Requirements vary, including during pregnancy and breastfeeding.
Lutein & Zeaxanthin Sources#
What Calk calculates. Lutein and zeaxanthin have no reference intake, so this card counts days instead: it appears when a portion with at least 1 mg of them shows up on at least half of your complete days. Dark leafy greens, corn, egg yolks, orange peppers and pistachios are typical sources, and these carotenoids accumulate in the retina.
AREDS2 studied a specific supplement formulation in people with age-related macular degeneration. Its result belongs to that formulation and that group Age-Related 2013.
Fat-Soluble Nutrient Context#
What Calk calculates. Calk looks at each sitting with a portion that carries about a sixth of the daily reference for vitamin A, E or K1. When at least three such sittings each had less than 5 g of fat, the card suggests adding some. Dietary fat can increase carotenoid absorption, but the effect varies by nutrient, food and person Brown 2004.
What you can do. If a vegetable-heavy meal contains virtually no fat, add an ordinary amount of oil, nuts, seeds, egg, dairy or avocado if it suits the meal. More fat is not automatically more absorption.
Spermidine Sources#
What Calk calculates. Calk tracks spermidine where specialist source data is available, including wheat germ, mushrooms, soy foods, legumes and some aged cheeses Eisenberg 2016. The card appears when the recorded average reaches about 10 mg a day over at least two weeks.
Autophagy and longevity are well beyond what a diary can show.