Fish Roe and Caviar: Paleo? Yes and No.

Roe vs. caviar

I hate to split hairs, but a distinction must be made between roe and caviar. The commonly edible eggs of fish and other aquatic animals (sea urchins, squid, shrimp, lobster, scallops etc.) represent the mature ovaries of the females of these species. Roe, unlike chicken eggs, do not present themselves as a single distinct egg, but rather the eggs occur attached to one another in connective tissue called “skeins.”⁴ Roe skeins can be consumed in their raw (“green”) unadulterated state or processed in a manner that separates individual eggs from one another.

When salt is added to separated fish eggs (a procedure called “brining”) it yields a food product called “caviar” which may also be subject to other “curing” processes and added chemicals.⁴ In the U.S. only sturgeon caviar can be labeled as “caviar.”⁴ Other salted fish roe such as salmon must be labeled with the fish from which it was made. So, salted cured salmon roe becomes “salmon caviar.”⁴

Sturgeon caviar is one of the most expensive foods in the world with a one ounce (30 gram) tin costing between $50 and $75. High end Osetra sturgeon caviar runs about $12,000 a kilo or about $378 for an ounce. Surprisingly, much less expensive caviar from salmon, herring, squid and other species is nutritionally superior to sturgeon caviar, particularly in regard to omega 3 fatty acids.^{20, 34, 39, 40}

Salt and caviar

Any and all caviars are by definition manufactured using salt.⁴ Accordingly, these processed foods would have been unavailable for consumption to our pre-agricultural ancestors. However there is little doubt that fresh, “green” unadulterated fish roe would have been relished.

Below in Table 2, you can see that fresh, non-processed fish roe represents a very low dietary source of sodium, whereas caviar is a concentrated source of sodium because of its processing with salt (NaCl).

Table 2. Sodium and energy (kcal) content per 100 grams of fish roe and caviar (45, 47)

The USDA recommended limit for daily sodium intake is 2,300 mg. Caviar eggs whether from sturgeon, salmon, herring or other species typically is packaged in 1 oz. (30 g) or 50 g (1.76 oz.) tins, but can be purchased in higher bulk quantities. Accordingly, a single 1 oz. (30 g) tin of caviar (on low end estimates) delivers a whopping 450 mg of sodium, whereas on high end values, it is more devastating still at 1162 mg of sodium.

From table 2 above, you can see that if you are going to eat roe, a better strategy (sodium wise) would be to consume fresh or frozen fish eggs without added salt.

In the U.S. fresh roe (“green”) and frozen roe is considerably more difficult to obtain than salted caviar, but not impossible. Go online and you can see a substantial number of retailers offering unprocessed fresh or frozen roe without salt. So the bottom line with salted caviar is to eat it infrequently or as a treat – better yet eat non-salted roe if you can find it.

Taste test of three non-sturgeon caviars

As long as I am writing about the scientific merits or lack thereof caviar and fish roe, I thought that it might be useful for me to give you my taste test impressions of three caviars (whitefish, capelin, lumpfish) which I purchased from our local World Market store. Below are my taste impressions of these three items.

1. I started off my culinary caviar adventures with Pacific Plaza Imports “Golden Whitefish Caviar.”⁴⁷

I bought a 50 g tin of this roe for $6.99 and carefully read the label which indicated the following items and their respective order: wild pasteurized whitefish roe, natural caramel coloring, truffle oil, water, tragacanth gum (as a stabilizer), salt, sodium benzoate (as a preservative).

Whew! That’s quite a list of non-Paleo ingredients. The label tells us that this whitefish caviar is harvested from a species known as Coregonus clupeaformis. By contrasting the slightly lower sodium content of this roe to capelin and lumpfish (Table 2) from the same company, I was expecting that my taste test would be somewhat positive or at least better than the capelin and lumpfish taste tests. Yuck! What a disappointment.

I gingerly picked out a clump of black whitefish caviar from the 50 g tin with a small hors d’oeuvres fork. Immediately, upon hitting my mouth, this tiny amount of roe sickened me with its overpowering salty taste to the point that I wanted to spit it out. It didn’t taste like any food I have ever eaten, but rather more like putting pure salt crystals on my tongue, but perhaps worse.

The fish oil seemed to cause the processed roe salt to permeate my tongue in a greater manner than salt itself. This food was so excessively salty that I have little desire to ever again eat caviar. But waitFor this review, I had to sample capelin and lumpfish caviar which both contain considerably more salt than whitefish.

2. Lumpfish and Capelin Caviar.

I pop open the lids from the tins of both lumpfish and capelin caviar and prepare to dive into them with my hors d’oeuvres fork. After a brief taste (only a few caviar eggs of each), I simply cannot tolerate the overpowering salty queasiness this food brings on.

Therapeutic health benefits of fresh fish roe

Fish roes are one of the most concentrated food sources of long chain omega 3 fatty acids EPA (20:5n3) and DHA (22:6n3).^{3-5, 13, 14, 19, 20, 26, 28, 34, 38-40} In numerous animal experiments roe consumption has been shown to improve various markers of health and well being and to reduce morbidity and mortality.^{11, 21, 22, 33, 44, 46} Only a handful of human studies has evaluated roe consumption in regard to this food’s potential therapeutic health effects.^{3, 4} So, if you can find unsalted roe, it represents one of the best dietary sources of healthful long chain omega 3 fatty acids.

The long chain omega 3 fatty acids found in roe are different from these beneficial fatty acids that you my get if you take fish oil or fish oil capsules. The omega 3 fatty acids (DHA and EPA) in fish roe are contained in phospholipids (structural fat) whereas EPA and DHA in fish oil are contained in the triglyceride (storage fat) fraction.⁴⁸ A number of studies suggest that ingestion of EPA and DHA bound to phospholipids are more readily absorbed and better utilized than EPA and DHA bound to triglycerides.^{3, 48 - 52} Accordingly, some scientists propose that the omega 3 fatty acids (EPA and DHA) found in fish eggs^{39, 48} and krill oil^{48, 50, 52} are more effective in enriching our bloodstream with these healthy nutrients. Unfortunately, few human experimental trials^{3, 50} have shown this proposed effect, and the best evidence to date indicates the “jury may still be out” on this concept because of experimental and methodological issues.^{8, 27}

Nevertheless, whether you consume fresh roe, krill oil, fish, fish oil, or fish oil capsules you will be doing your body a favor by ingesting long chain omega 3 fatty acids which reduce the risk of cardiovascular disease, cancer and other pro-inflammatory illnesses.

Fish roe lectins and allergy

When most people in the Paleo diet community see the word, “lectin” it typically conjures up images of plant foods such as whole grains and legumes which contain lectins such as wheat germ agglutinin (WGA in wheat) and phytohemagglutinin (PHA in beans).

In experimental animals, both of these lectins have been shown to bypass the gut barrier and promote adverse physiological effects.^{53, 54} To date, these lectins have been scarcely studied in human tissue (in vitro) experiments and almost never examined in living humans (in vivo studies).⁵⁵

Rarely do Paleo dieters recognize that certain animal foods may also contain various antinutrients, including lectins. Starting in the late 1970s, fish roe from most species was discovered to be a significant source of certain lectins.^56-59 As more recent work has confirmed, most fish roe lectins belong to a category of lectins called rhambose-binding lectins (RBLs).^{12, 16, 23, 32, 36, 37, 41, 42}

The biological function of RBLs in fish eggs seems to primarily involve activation of innate immunity, host pathogen interaction and inflammatory reactions in various fish tissues.^{32, 41, 42} Multiple RBLs (CSL1, 2 and 3) from chum salmon roe induced production of the pro-inflammatory cytokines (IL-1 β1, IL-2β2, TNFα1 and IL-8) in fish macrophages.⁴² To date no experimental mammal, or human studies have determined if RBLs from fish roe interact with our immune systems to produce inflammation or undesired health effects.

However, substantial literature exists showing that fish roe consumption represents a common food allergen in humans, particularly children.^{7, 15, 24, 18, 29, 30, 31, 35} The primary allergen in fish roe is known as “ ß`- component”^{18, 29} and may cause severe anaphylactic reactions.

Conclusions

In the U.S., caviar is rarely eaten by the average consumer, whereas it is a common food item in Japan and other countries worldwide. Because caviar represents a concentrated salt source, it should be rarely consumed or avoided by regular Paleo dieters. If you can find it, fresh or frozen fish roe of any species represents one of the most concentrated dietary sources of the healthful, long chain, omega 3 fatty acids, EPA and DHA. Eat it if you can. However, if you experience an allergenic reaction – hives, itching skin, running nose, difficulty breathing, rashes, etc. – know that fish roe is a common dietary allergen, and the immunological flip side of allergy frequently involves autoimmunity.

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