Hearts of palm: two USDA rows that disagree about the same vegetable

Hearts of palm is a food our evidence base barely covers. In our corpus there is no randomised trial, no cohort study and no meta-analysis of it, under the English name or under palmito, and nothing at all on how the body handles it. What we do have is worth knowing before you open a jar. USDA carries two composition records for this vegetable, raw and canned, and they differ about tenfold. Raw holds 1806 mg potassium per 100 g against 177 mg canned, 0.644 mg copper against 0.133 mg, and 0.81 mg vitamin B6 against 0.022 mg. Those are two independent entries with no per-sample spread published for either one. The gap between them cannot be separated from differences in sampling and analysis, and neither record is a modern Foundation Foods sample. The canned entry is the one that describes what comes out of a jar. A 1978 review of processing research, mostly work at a Brazilian food institute, names the two problems canning has always had with this vegetable. The white flesh discolours, and the product has to be acidified safely because otherwise Clostridium botulinum can grow in it. That review reports both solved in pilot plant work rather than in the canneries.

The numbers, per 100 g

How much is actually in it

• Raw hearts of palm carry 1806 mg potassium, 0.644 mg copper and 0.81 mg vitamin B6 per 100 g against 177 mg, 0.133 mg and 0.022 mg in the canned record, so the same food differs about tenfold between the two USDA entries. — the two USDA SR Legacy composition records for this food, hearts of palm raw (FDC 167714) and hearts of palm canned (n = 2 records) Evidence E source
  Potassium 1806 against 177 mg per 100 g, copper 0.644 against 0.133 mg, vitamin B6 0.81 against 0.022 mg

What a real portion looks like

• One heart of palm weighs 40 g and a cup of cooked hearts of palm weighs 145 g, so a cup holds between three and four hearts. — household portion measures recorded for Palm hearts, cooked (n = 2 measures) Evidence E source
  1 heart 40 g, 1 cup 145 g

What cooking and storage change

• Boiled in a little water and drained, a vegetable of this USDA group keeps 70 percent of its folate, 80 percent of its vitamin C, 90 percent of its potassium and vitamin B6, and 95 percent of its copper. — USDA retention factors for the group Vegetables and Vegetable Products, code 11, boiled in little water and drained (n = 16 nutrients in the row) Evidence E source
  Folate 70 percent retained, vitamin C 80 percent, potassium 90 percent, vitamin B6 90 percent, copper 95 percent
• Canning hearts of palm has two standing technical problems: the white flesh discolours, and the product has to be acidified safely because otherwise Clostridium botulinum can grow in it. — review of processing research on canned palmito, mainly work done at ITAL in Campinas, Brazil Evidence D source
  —

Safety, limits and interactions

• US rules class canned hearts of palm as an acidified food, which must reach and hold a finished equilibrium pH of 4.6 or lower. — regulatory requirement for acidified foods sold in the United States Evidence E source
  Finished equilibrium pH 4.6 or lower, achieved within the scheduled process time and maintained

The bottom line

Read the jar, not the raw row. One heart of palm weighs 40 g and a US cup of cooked hearts weighs 145 g, so a cup runs to three or four hearts. Any per-portion nutrient figure you see is recalculated from the per 100 g value rather than measured on the portion itself. For home cooking there is no measurement on this vegetable at all. USDA publishes a retention factor covering the whole group of other vegetables boiled in a little water and drained. That row keeps 70 percent of folate, 80 percent of vitamin C, 90 percent of potassium and vitamin B6 and 95 percent of copper. It is set for the group rather than for palm hearts, on a table page dated 1975. It says nothing about the brine in a jar, which is where the potassium of a canned vegetable goes. The one safety rule we have is about the container rather than about you. United States regulation classes canned hearts of palm as an acidified food and requires a finished equilibrium pH of 4.6 or lower, reached inside the scheduled process time and held there. Acidification is what stops Clostridium botulinum in a product like this, and home jarring is precisely what the rule was written against. Beyond that we hold no card on allergy, on pregnancy, on children or on medicines for this food. That silence is a gap in what we found, and it is not a clearance.

Sources

1. hpal-r1-03 · food composition dataset
   Hearts of palm, raw (FDC 167714): potassium 1806 mg, copper 0.644 mg, vitamin B6 0.81 mg per 100 g
   USDA SR Legacy, FoodData Central, record 167714 · checked 2026-09-24
2. hpal-r1-04 · portion dataset
   Palm hearts, cooked (2709954): 1 heart 40 g, 1 cup 145 g
   USDA FNDDS, Palm hearts cooked, record 2709954 · checked 2026-09-24
3. hpal-r1-05 · retention factor dataset
   VEG,OTHER,BLD,LITTLE WATER,DRAINED (Retn_Code 3774): folate_total_ug 70%, vitamin_c_mg 80%, potassium_mg 90%, vitamin_b6_mg 90%, copper_mg 95%
   USDA Table of Nutrient Retention Factors Release 6, 2007, Retn_Code 3774 · checked 2026-09-24
4. hpal-r3-01 · food technology review
   There are two main technical problems in palmito processing: discoloration of the naturally white product and safe acidification to inhibit Clostridium botulinum growth.
   J Food Prot, 1978 · checked 2026-09-24
5. hpal-r3-02 · regulation
   Acidified foods shall be so manufactured, processed, and packaged that a finished equilibrium pH value of 4.6 or lower is achieved within the time designated in the scheduled process and maintained in all finished foods.
   21 CFR 114.80(a)(1), Acidified Foods · checked 2026-09-24