Olive benefits: 735 mg of sodium per 100 g — and the trials are on the oil, not the fruit

Key benefits

1. 01Nutrition data

   735 mg of sodium, 8 mg of potassium — that is what the cure did

   Per 100 g of canned ripe olives:

   • 116 kcal
   • Fat 10.9 g — saturated 2.28 g; most of the rest monounsaturated
   • Sodium 735 mg
   • Carbohydrate 6.04 g, fibre 1.6 g, sugar 0 g
   • Protein 0.84 g
   • Iron 6.28 mg, calcium 88 mg, copper 0.251 mg
   • Vitamin E 1.65 mg, vitamin A 17 µg, beta-carotene 198 µg, vitamin K 1.4 µg
   • Potassium 8 mg
   • Cholesterol 0

   Per olive (4 g):

   	100 g (about 25)	One olive (4 g)	Five olives (20 g)
   Energy	116 kcal	5 kcal	23 kcal
   Sodium	735 mg	29 mg	147 mg
   Fat	10.9 g	0.4 g	2.2 g

   Start with the sodium. The WHO recommends under 2,000 mg a day. 100 g of olives is 37% of that. Though few people eat 100 g in one sitting. Five olives is 147 mg, around 7% of the day.

   What matters more than the olive is the company it keeps — pizza, pasta, a salty salad dressing, a snack plate beside cheese. Often the olive is not the problem; the whole plate the olive sits on is salty.

   Look at the 8 mg of potassium. That is the fingerprint of processing. Most fruits and vegetables carry far more potassium than sodium. The olive is inverted, at roughly 90 to 1. The potassium that was in the fresh fruit left into the brine, and sodium took its place.

   The 10.9 g of fat is mostly monounsaturated — oleic acid, olive oil's main component, in the form it occupies in the fruit. Saturated fat is low at 2.28 g, and cholesterol is zero.

   Sugar is 0 g. It is a fruit with no sweetness; fermentation and curing consumed it.

   The 6.28 mg of iron is unusually high, a figure rarely seen in a plant food. It belongs specifically to canned ripe olives. Black ripe olives are darkened with ferrous gluconate, an iron salt used to fix the colour, and it appears on the ingredient list. So this iron came from processing rather than from the fruit, and green olives or other cures give different numbers.

   The vitamin E (1.65 mg) and beta-carotene (198 µg) sit alongside the fat, which favours their absorption.

2. 02Not established

   The evidence for olives is evidence for olive oil — the two should not be merged

   This entry is about what this site does not know.

   The Mediterranean diet is among the most studied eating patterns in nutrition. And the names of those studies nearly always contain olive oil. The oil, not the fruit.

   Why the distinction matters.

   First, the intervention was oil. Participants in Mediterranean diet trials were generally given extra virgin olive oil, at doses set in tablespoons per day. There is no basis for transferring those results to cured olive fruit.

   Second, the composition differs.

   	Olive fruit (canned)	Olive oil
   Sodium	735 mg/100 g	effectively 0
   Fat	10.9 g/100 g	100 g/100 g
   Fibre	1.6 g	0
   Polyphenols	largely lost in curing	retained depending on pressing

   Same tree, different foods. The fruit is salty and the oil is not. The oil is entirely fat; the fruit is around a tenth.

   Third, curing changes the composition. Raw olives are bitter because of oleuropein, and making them edible means drawing it out with lye or brine. The compound that makes them bitter is the polyphenol. The process that makes them edible reduces it.

   What this site can say now:

   • No clinical trial feeding olives and measuring outcomes has been found yet. One may exist that this site has not found
   • So this page contains no sentence of the form "eating olives improves X"
   • Evidence on olive oil is handled separately in this site's olive oil entry
   • This entry will be updated as evidence is found

   Between observing that Mediterranean populations live long and claiming that olives are the reason lies a long distance. That diet also contains fish, vegetables, pulses, whole grains and nuts, along with a walking life and the hours at which people eat. Crediting a single food misreads the diet.

3. 03Not established

   "Black olives are the riper ones" is not always true

   This entry is about the label.

   It is commonly explained that black olives are riper and green olives less ripe. Partly true, partly not.

   Some olives do ripen black naturally. They turn black or purple on the tree and are cured in salt or brine — named varieties such as Kalamata belong here.

   But the uniformly jet-black canned olive is different. Those are under-ripe olives treated with lye and darkened by blowing air through to oxidise them, with ferrous gluconate used to fix the colour. It is printed on the ingredient list. That is why the 6.28 mg of iron in the table above is so unusually high.

   So look at them separately.

   • Perfectly uniform black, canned, pitted into rings → usually darkened by oxidation
   • Colour varying from olive to olive, wrinkled, stone in → often naturally ripened and cured

   This is not a claim that one is better. This site holds no clinical data comparing them. But you should know which one the table above describes. It is for canned ripe olives, and green olives and naturally cured olives differ in both sodium and iron.

   One thing to check — the sodium on the label. The same fruit varies widely per 100 g depending on the cure. The number on the back of the jar is more accurate than the name of the variety.

   To cut the salt, rinse them once in water: the surface brine washes off. The salt that has soaked in stays.

How to eat it well

What to watch out for