LemonsFruit
29
kcal / 100g
61
kcal / 1 cup, sections
1 thing to watch for
Informational only, not medical advice. Always verify against the physical product label — data may be incomplete or out of date.
Nutrition Facts (per 100g)
| Nutrient | Amount | %DV |
|---|---|---|
| Energy | 29kcal | — |
| Protein | 1.1g | 2% |
| Total lipid (fat) | 0.3g | 0% |
| Fatty acids, total saturated | 0.039g | 0% |
| Cholesterol | 0mg | 0% |
| Carbohydrate, by difference | 9.32g | 3% |
| Fiber, total dietary | 2.8g | 10% |
| Total Sugars | 2.5g | — |
| Sodium, Na | 2mg | 0% |
Vitamins & Minerals
Vitamin C contributes to normal collagen formation for the normal function of blood vessels EU register →
Vitamin C contributes to normal collagen formation for the normal function of bones EU register →
Vitamin C contributes to normal collagen formation for the normal function of cartilage EU register →
Vitamin C contributes to normal collagen formation for the normal function of gums EU register →
Vitamin C contributes to normal collagen formation for the normal function of skin EU register →
Vitamin C contributes to normal collagen formation for the normal function of teeth EU register →
Vitamin C contributes to normal energy-yielding metabolism EU register →
Vitamin C contributes to normal functioning of the nervous system EU register →
Vitamin C contributes to normal psychological function EU register →
Vitamin C contributes to the normal function of the immune system EU register →
Vitamin C contributes to the reduction of tiredness and fatigue EU register →
Vitamin C contributes to the regeneration of the reduced form of vitamin E EU register →
Vitamin C increases iron absorption EU register →
Diet Compatibility
- VeganYes
Yes — Lemons is vegan.
Based on Open Food Facts ingredient analysis. How we set this
- VegetarianYes
Yes — Lemons is vegetarian.
Based on Open Food Facts ingredient analysis. How we set this
- Palm Oil FreeYes
Yes — Lemons is palm oil free.
Based on Open Food Facts ingredient analysis. How we set this
- Gluten-FreeYes
Yes — Lemons is gluten-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
- Dairy-FreeYes
Yes — Lemons is dairy-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
- Nut-FreeYes
Yes — Lemons is nut-free.
Based on the ingredient list and allergen data recorded in Open Food Facts (covers tree nuts and peanuts). How we set this
- Soy-FreeYes
Yes — Lemons is soy-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
- Egg-FreeYes
Yes — Lemons is egg-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
- KetoYes
Yes — Lemons is keto-friendly (6.52 g net carbs per 100g, within the ≤10 g net carbs bar). (may not account for sugar alcohols; per-100g basis is a rougher heuristic than per-serving.)
≤5g net carbs per serving — our bar, not a regulatory standard. How we set this
- Low-CarbYes
Yes — Lemons is low-carb (6.52 g net carbs per 100g, within the ≤15 g net carbs bar). (may not account for sugar alcohols.)
≤15g net carbs per serving — our bar, not a regulatory standard. How we set this
- Low-SugarYes
Yes — Lemons is low in sugar (2.5 g sugar per 100g, within the ≤5 g sugar bar).
≤5g sugar per serving — our own criterion; the FDA defines none. How we set this
- High-ProteinNo
No — Lemons is not high in protein (1.1 g protein per 100g, below the ≥10 g protein bar).
≥10g protein per serving — FDA 21 CFR 101.54 (≥20% DV). How we set this
- Low-FatYes
Yes — Lemons is low-fat (0.3 g fat per 100g, within the ≤3 g fat bar).
≤3g fat per serving — FDA 21 CFR 101.62. How we set this
- Low-CalorieYes
Yes — Lemons is low-calorie (29 kcal per 100g, within the ≤40 kcal bar).
≤40 kcal per serving — FDA 21 CFR 101.60. How we set this
Read the sourced research
Raw lemon has 0mg cholesterol and no animal-derived nutrients in USDA's profile, consistent with a whole-plant, vegan food. A medium lemon runs roughly 5-6g net carbs (total carbs minus fiber), a small enough slice of a typical ~20-25g/day keto budget to use freely in small amounts. [5]
Per the Monash University app, fresh lemon juice tests low-FODMAP up to about 20mL (1 tbsp), with a moderate fructan level appearing around 172mL; lemon zest is low-FODMAP up to about 3g. Exact thresholds vary somewhat between reported sources, so read these figures as approximate rather than a hard line. [6]
Lemon shares panallergen proteins with other Rutaceae fruits (lime, orange, grapefruit, tangelo), so cross-reactivity is expected, though it isn't extensively documented. Its known allergens, Cit l 1 and Cit l 3, can cross-react with the peach allergen Pru p 3 — but not every citrus-allergic person reacts to every citrus fruit the same way. [7]
A 2013 study found 39% of grass-pollen-allergic children and young adults tested positive on a lemon skin-prick test. That signals pollen-food cross-reactivity — also called oral allergy syndrome — rather than a true, independent lemon allergy. [8]
Many allergic reactions to citrus fruit are actually oral allergy syndrome — pollen-food cross-reactivity from proteins shared between certain pollens and citrus, not a classic food allergy. This distinction matters because it usually explains milder mouth or lip symptoms rather than a systemic reaction. [9]
Health Benefits
About 4 fl oz (125mL) of lemon juice a day can meaningfully raise urinary citrate without raising oxalate in people whose citrate runs low, which lowers the two chemical drivers behind calcium-oxalate kidney stones. Researchers note that not everyone with stones has low citrate to begin with, and controlled trials confirming fewer repeat stones are still limited. [1]
Lemon's vitamin C and citric acid can improve how well the body absorbs non-heme iron from plant foods, which may support people prone to iron-deficiency anemia. The soluble pectin fiber in lemon pulp may promote fullness, but that effect comes from the pulp — lemon juice alone contains no pectin. [2]
In a small randomized crossover trial, lemon juice (but not tea) lowered the peak blood glucose rise after eating bread by about 30%, compared with water. The peak also came more than 35 minutes later — though this comes from one small study in healthy volunteers, not people with diabetes. [3]
Storage & Buying Tips
Keep ripe lemons in the refrigerator in a loosely sealed plastic bag to help them last longer. Don't wash them until you're ready to use them — added moisture speeds spoilage. [4]
Frequently Asked Questions
Can you eat lemons raw every day, and how many lemons can you eat in a day?
There's no strict nutritional ceiling — most people can eat a lemon a day without trouble. The real limits are personal tolerance: acid wearing on tooth enamel, and heartburn or reflux discomfort for some people.
From a carb-counting angle, a medium lemon runs about 4-6g net carbs. Even two lemons a day would still fit comfortably inside a typical ~20-25g/day keto budget. [5]
Are lemons safe to consume during pregnancy?
Yes, in normal food amounts. Some pregnant people also find lemon scent or aromatherapy (not ingested oil) helpful for nausea.
The main pregnancy-specific caution is dental: pregnancy already raises the risk of enamel erosion and gum issues, and frequent citrus intake adds to that. Moderate amounts plus good oral hygiene are the practical takeaway. [10]
Can lemons cause allergic reactions?
True lemon allergy is rare, but reactions do happen. Most are oral allergy syndrome — itching or swelling around the mouth in people already allergic to grass or birch pollen.
Case reports describe rarer, more serious events too: anaphylaxis tied to lemon-scented soap in someone with a citrus-seed sensitivity, and one documented case of citrus-triggered exercise-induced anaphylaxis. Touching lemon peel can also irritate skin, causing a reaction called phytophotodermatitis. [9]
Does cooking or juicing lemons destroy the vitamin C?
Partly. Vitamin C breaks down with heat, time, light and air exposure, and lemon juice loses some of it the longer it's stored.
One study found juice held onto about 70% of its original vitamin C after 8 weeks at 28°C. A quick squeeze over a hot (not actively cooking) dish barely touches the vitamin C content, though — it's not a reason to skip the flavor. [11]
Why do lemons hurt tooth enamel?
Lemon juice sits at a pH of roughly 2-3, well below the ~5.5 point where enamel starts to soften. Citric acid attacks the mineral structure directly and pulls calcium out of the enamel surface.
Lab studies on real tooth enamel confirm this erosion, and it gets worse the lower the pH, the stronger the acid, and the longer the exposure. [12]
Is it safe to swallow lemon seeds?
Generally yes — an intact lemon seed swallowed whole just passes through a healthy adult's digestive tract within a day or two, since its hard shell resists digestion. Unlike stone-fruit pits (cherry, apricot, peach), citrus seeds aren't documented as a cyanogenic-compound risk in published research.
The realistic downsides are a choking hazard if swallowed carelessly, and mild stomach upset if a large handful is chewed and swallowed at once. [13]
Found in these products
None of the products in our database currently contain Lemons.
Sources & Last Updated
Nutrition data: USDA FoodData Central, “Lemons, raw, without peel” (SR Legacy, fdcId 167746), updated 2026-08-27.
Research reviewed 2026-08-27.
- Gul et al., Korean Journal of Urology (2014-11-27)
- Healthline Media — 6 Evidence-Based Health Benefits of Lemons (2019-01-07)
- Lemon juice, but not tea, reduces the glycemic response to bread in healthy volunteers: a randomized crossover trial - PubMed (2021-01-31)
- Lemons Household Food Fact Sheet
- Lemons, raw, without peel - Nutrients - SR Legacy | USDA FoodData Central
- Dr. Rachel’s Best Low-FODMAP Lemon Recipes; Gluten-free (2021-09-01)
- f208 Lemon | Thermo Fisher Scientific
- Iorio et al., PLoS ONE (2013-01-03)
- Healthline Media — Do You Have a Citrus Allergy? Learn the Symptoms (2017-04-04)
- Medical News Today — Is lemon good for pregnancy? Water, tea, and juice (2020-03-11)
- Lee et al., Food Science and Biotechnology (2017-12-11)
- Dental erosion
- Yahoo — Yahoo Health (2026-04-09)