By Paleo Life Coach Editorial Team · Last updated September 25, 2026 · Nutrient data from USDA FoodData Central
Cutting dairy, grains and legumes removes a lot of processed food from your plate. It also removes the foods that supply much of the calcium, iodine and fiber in a typical diet, and fortified foods that supply vitamin D. Paleo diet calcium is the gap people ask about most, but it isn’t the only one. This guide shows what trials actually measured when people went paleo, how much of each nutrient you need, and exactly which paleo foods close each gap, with USDA numbers.
The quick version: A paleo diet can fall short on calcium, vitamin D, iodine and sometimes fiber. Trials found paleo eaters took in about 290 mg less calcium and 48 mcg less iodine a day. Close the gaps with canned fish with bones, cooked collards or kale, tahini and chia for calcium; fatty fish for vitamin D; seafood, eggs or iodized salt for iodine.
Why does the paleo diet create nutrient gaps?
Because the foods it removes are major sources of specific nutrients. Dairy is a leading source of calcium and iodine in Western diets; fortified milk and cereals supply vitamin D; whole grains and legumes supply fiber. Harvard’s review of the diet warns that excluding whole grains and dairy may increase the risk of deficiencies such as calcium, vitamin D and B vitamins unless they’re eaten from allowed foods or a supplement (Harvard T.H. Chan School of Public Health). It also notes that meeting calcium needs from greens and fish bones alone would take five or more servings a day.
These aren’t just theoretical concerns. Randomized trials measured them:
| Trial | Who and how long | What happened to intake or status |
|---|---|---|
| Genoni et al., 2016 | 39 healthy women, 4 weeks, paleo vs Australian guidelines | Paleo group ate 292 mg/day less calcium, 47.9 mcg/day less iodine and 1,055 mg/day less sodium |
| Manousou et al., 2018 | 70 postmenopausal women with overweight or obesity, 2 years, paleo vs Nordic recommendations | Median urinary iodine fell from 71 to 36 mcg/L at 6 months in the paleo group; unchanged on the control diet. Authors suggest considering iodine supplementation on paleo |
| Jönsson et al., 2009 | 13 adults with type 2 diabetes, crossover, 3 months per diet | Paleo diet was lower in calcium and higher in several vitamins than the diabetes diet |
Sources: Genoni 2016, Manousou 2018, Jönsson 2009 (abstracts on PubMed).
The same trials show paleo improving other things, such as more beta-carotene and lower sodium. The point isn’t that paleo is deficient by nature; it’s that four nutrients need a plan. For the overall evidence on benefits, see paleo diet health benefits.
How much calcium, vitamin D, iodine and fiber do you need?
Targets depend on age and life stage. These are the adult reference values:
| Nutrient | Adult target | Higher needs | Source |
|---|---|---|---|
| Calcium | 1,000 mg/day (ages 19–50; men 51–70) | 1,200 mg/day for women 51–70 and everyone over 70 | MedlinePlus |
| Vitamin D | 600 IU (15 mcg)/day, ages 19–70 | 800 IU (20 mcg)/day over 70 | MedlinePlus |
| Iodine | 150 mcg/day | 220 mcg pregnancy; 290 mcg breastfeeding | Harvard, Iodine |
| Fiber | At least 25–35 g/day | — | Harvard, Fiber |
On food labels, the FDA uses 1,300 mg for calcium, 20 mcg for vitamin D, 150 mcg for iodine and 28 g for fiber as Daily Values (FDA), so “%DV” on a paleo-friendly product is measured against those numbers.
What are the best paleo calcium sources?
Canned fish eaten with the bones and cooked leafy greens from the cabbage family are the strongest paleo calcium sources. Harvard notes that collard and turnip greens and canned bone-in sardines and salmon are absorbed well, while spinach, despite its high listed calcium, contains oxalates that bind calcium so little is absorbed.
| Food (serving) | Calcium (mg) | Vitamin D (mcg) | Fiber (g) | Calories |
|---|---|---|---|---|
| Sardines, canned in oil, with bones (1 can, 92 g) | 351 | 4.4 | 0 | 191 |
| Collard greens, cooked (1 cup, 190 g) | 268 | 0 | 7.6 | 63 |
| Spinach, cooked (1 cup, 180 g) — poorly absorbed | 245 | 0 | 4.3 | 41 |
| Turnip greens, cooked (1 cup, 144 g) | 197 | 0 | 5.0 | 29 |
| Pink salmon, canned, with bones and liquid (3 oz, 85 g) | 183 | 11.6 | 0 | 110 |
| Chia seeds (1 oz, 28 g) | 179 | — | 9.8 | 138 |
| Kale, cooked (1 cup, 118 g) | 177 | 0 | 4.7 | 42 |
| Bok choy, cooked (1 cup, 170 g) | 158 | 0 | 1.7 | 20 |
| Tahini, roasted kernels (2 tbsp, 30 g) | 128 | 0 | 2.8 | 178 |
| Almonds (1 oz, 28 g) | 76 | 0 | 3.5 | 164 |
| Dried figs (5 figs, 42 g) | 68 | 0 | 4.1 | 105 |
| Broccoli, cooked (1 cup, 156 g) | 62 | 0 | 5.1 | 55 |
| Orange (1 medium, 131 g) | 52 | 0 | 3.1 | 62 |
| Reference: milk, 2%, vitamin D added (1 cup) | 293 | 2.9 | 0 | 122 |
| Reference: cheddar cheese (1 oz) | 201 | 0.2 | 0 | 114 |
Method: USDA FoodData Central SR Legacy values per 100 g (FDC IDs 175139, 170407, 168463, 170466, 173690, 170554, 169238, 170391, 170189, 170567, 174665, 169967, 169097, 171267, 173414) scaled to USDA portion weights. “—” means USDA reports no value for that nutrient.
Worked example: a dairy-free day with 1,054 mg of calcium
Here’s how the numbers add up in a real day, using the table:
- Breakfast: chia pudding with 1 oz chia seeds (179 mg) and 1 medium orange (52 mg)
- Lunch: 1 can sardines with bones on greens (351 mg) with 2 tbsp tahini-lemon dressing (128 mg)
- Snack: 1 oz almonds (76 mg)
- Dinner: any protein with 1 cup cooked collard greens (268 mg)
Total: 1,054 mg of calcium, just over the 1,000 mg adult RDA. The tahini-lemon sauce from our paleo salad dressing recipes is an easy way to add it.
Now remove the fish. Swapping the sardines for 1 cup of cooked kale (177 mg) and 5 dried figs (68 mg) gives 948 mg across more servings, and that’s with generous greens every day. This is what Harvard means when it says dairy-free calcium takes deliberate effort. If you tolerate dairy, the Primal approach, which allows full-fat dairy, is one way around the problem.
How do you get enough vitamin D on paleo?
Few foods contain much vitamin D, so food alone rarely covers it on any diet. The best paleo food sources are fatty fish and UV-exposed mushrooms:
| Food (serving) | Vitamin D (mcg) | Share of 15 mcg adult RDA |
|---|---|---|
| UV-exposed portabella mushrooms, grilled (1 cup sliced, 121 g) | 15.9 | 106% |
| Sockeye salmon, cooked (3 oz, 85 g) | 14.2 | 95% |
| Pink salmon, canned with bones (3 oz, 85 g) | 11.6 | 77% |
| Sardines, canned in oil (1 can, 92 g) | 4.4 | 29% |
| Egg, hard-boiled (1 large) | 1.1 | 7% |
USDA FoodData Central SR Legacy (FDC IDs 169377, 173692, 173690, 175139, 173424). Only mushrooms labeled as UV-treated have these levels.
Harvard explains that the RDA assumes minimal sun exposure, and that the body also makes vitamin D in skin exposed to sunlight (Harvard, Vitamin D). How much you make depends on season, latitude, skin tone and age. If you eat fatty fish less than twice a week, live far from the equator or are over 70, ask your doctor whether a blood test or supplement makes sense for you, rather than guessing a dose.
Is the paleo diet low in iodine?
It can be. The 2-year Swedish trial notes that paleo excludes two of the largest iodine sources, table salt (when iodized) and dairy, and it measured a sharp drop in urinary iodine. Harvard lists the main iodine sources as seaweed, fish and shellfish (cod, canned tuna, oysters, shrimp), iodized salt, dairy, eggs, beef liver and chicken.
Practical fixes that fit paleo:
- Use iodized salt when you salt food. Many paleo recipes call for sea salt or pink salt, which usually aren’t iodized. Check the label.
- Eat seafood two or more times a week, especially cod, shrimp and canned tuna.
- Keep eggs in rotation.
- Be careful with seaweed. Harvard notes that even a slight increase above the RDA can trigger thyroid problems in sensitive people, and seaweed iodine varies widely. Don’t use kelp supplements without medical advice.
If you’re pregnant, breastfeeding or planning pregnancy, iodine needs rise to 220–290 mcg, so talk to your doctor about whether a prenatal vitamin with iodine is right for you.
Does paleo give you enough fiber?
It depends entirely on how you build it. A paleo day based on vegetables, roots, fruit and nuts can beat typical intakes easily; our USDA-calculated sample day reached 43 g. A paleo day built on meat, eggs and paleo baked goods can fall below 15 g. Harvard notes most Americans get only about 15 g a day against a need of at least 25–35 g.
The highest-fiber paleo foods per serving from the USDA data: chia seeds (9.8 g per ounce), raspberries (8.0 g per cup), collards (7.6 g per cup), artichoke (6.8 g per medium artichoke), avocado (6.7 g per half), and baked sweet potato (6.6 g per cup). See how fiber and carbs fit together in our guide to paleo diet carbs per day.
A weekly checklist to close paleo nutrient gaps
- Calcium: at least one canned-fish-with-bones meal and cooked collards, kale, turnip greens or bok choy most days; tahini or chia a few times a week.
- Vitamin D: fatty fish at least twice a week; UV-treated mushrooms as a bonus; discuss testing with your doctor if intake is low.
- Iodine: iodized salt in cooking, seafood twice a week, eggs regularly.
- Fiber: vegetables at every meal, fruit or berries daily, a starchy root at one meal.
- Review: if you’ve followed paleo for months and aren’t sure you’re covering these, a registered dietitian can analyze a food log.
Our list of common paleo diet mistakes covers other pitfalls, like leaning on packaged “paleo” foods.
Frequently asked questions about paleo diet calcium and nutrients
How do you get calcium on a paleo diet?
Eat canned sardines or salmon with the bones, cooked collard, turnip or kale greens, bok choy, tahini, chia seeds and almonds. A day with one can of sardines, a cup of collards, 2 tablespoons of tahini, an ounce of chia, an ounce of almonds and an orange provides about 1,054 mg, above the 1,000 mg adult RDA.
Do you need supplements on the paleo diet?
Not automatically. Many people can meet calcium, iodine and fiber needs from paleo foods with planning. Vitamin D is harder to get from food on any diet. Whether you need a supplement depends on your intake, sun exposure, age and health, so ask your doctor or a registered dietitian rather than self-prescribing.
Is the paleo diet low in iodine?
It can be. Paleo removes dairy and often iodized salt, two major iodine sources. In a 2-year trial, urinary iodine in the paleo group fell by about half within 6 months. Using iodized salt, eating seafood twice a week and including eggs helps. Pregnant and breastfeeding women need more iodine and should get medical advice.
Is spinach a good calcium source on paleo?
Not really. Cooked spinach lists about 245 mg of calcium per cup in USDA data, but Harvard notes its oxalates bind calcium so very little is absorbed. Collard greens, turnip greens, kale and bok choy are better choices because their calcium is absorbed well.
Can the paleo diet cause vitamin D deficiency?
Paleo removes fortified milk and cereals, which supply some vitamin D in a typical diet, so intake can drop if you don’t eat fatty fish. Deficiency depends mostly on sun exposure, season, skin tone and age. Eating salmon or sardines regularly helps; your doctor can check your level with a blood test.
Your next step: fix calcium first
Of the four gaps, calcium is the one most paleo eaters miss, and it’s the easiest to measure with the table above. Add up yesterday’s calcium using the serving values, and if you’re under 1,000 mg, add one canned-fish meal and one serving of cooked greens a day. Then work through vitamin D and iodine. For the rest of the fundamentals, see the complete paleo diet guide.
Consider this general nutrition reading, not a replacement for medical advice. Talk to your doctor or a registered dietitian before starting supplements, especially if you are pregnant, breastfeeding, have a thyroid or kidney condition, or take medication.
Research cited in this guide
- Diet Review: Paleo Diet – Harvard T.H. Chan School of Public Health
- Calcium in diet – MedlinePlus, National Library of Medicine
- Vitamin D – MedlinePlus, National Library of Medicine
- Vitamin D – Harvard T.H. Chan School of Public Health
- Iodine – Harvard T.H. Chan School of Public Health
- Fiber – Harvard T.H. Chan School of Public Health
- A Paleolithic-type diet results in iodine deficiency: a 2-year randomized trial (Manousou et al., 2018) – PubMed
- Paleolithic vs. Australian Guide to Healthy Eating diets: a 4-week randomised trial (Genoni et al., 2016) – PubMed
- Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes (Jönsson et al., 2009) – PubMed
- Daily Value on the Nutrition and Supplement Facts Labels – U.S. Food and Drug Administration
- FoodData Central – U.S. Department of Agriculture