Prologue
“... gains in longevity achieved by modern medicine are ending, and our children may actually die at an earlier age. Why? Labor-saving devices have caused people to become much more sedentary than in the past, modern society is increasingly stressful, and, most importantly, food consumption has become harmful. The major part of our diet is now made up of nutritionally unbalanced processed foods that are diabolically concocted with sugar, bad fats, salt, and artificial flavors to stimulate overeating and consequent obesity and health problems. It is critical that the processed foods currently making up the majority of our diet be reformulated to increase health. In this regard, sea buckthorn is like manna from heaven.”
Ernest Small, PhD, Principal Research Scientist, Agriculture and Agri-Food Canada, Ottawa, Foreword in Reference 2.

A symbol of abundance dating back 2500 years, the cornucopia (“horn of plenty”) provided whatever was desired by its owner. Original depictions were of a goat's horn filled with fruits and flowers. For the natural products industry's current need for novel flavors, colors and nutrients, a single plant teeming with phytochemicals may add to a horn of plenty.

Although not well-known in Western science, seaberry (sea buckthorn, Hippophae rhamnoides L., family Elaeagnaceae) (1) may be one of Nature's most nutrient-dense plants. It has abundant micronutrient and phytochemical contents, including extraordinary vitamin C and E levels, essential minerals and amino acids, carotenoid and phenolic pigments, dense sterol amounts, and unusual pulp and seed richness of omega-3 and -6 fatty acids.

Seaberry offers a cornucopia for developing valuable consumer products. However, despite abundant supplies from vast wild and cultivated acreage across China, Russia, northern Europe and India, it is mostly undeveloped on a significant commercial scale and remains unrecognized in mainstream markets. Estimated global seaberry product sales in 2005 were $330 million, mostly by northern European and Scandinavian consumers (A. Wähling, personal communication). This essay provides scientific background, a review of nutrient and phytochemical features, and survey of topics in recent medical research.

Fig. 1. Russian seaberries. courtesy – Axel Wähling, Magdeburg, Germany

Cultivation and uses. Native to Asia and northern Europe, more than 90% of the world's seaberry supply comes from the wilds of northern China, particularly Inner Mongolia where it has been harvested by peasants for some 15 centuries. In China alone, seaberry grows wild on more than one million hectares (2.5 million acres) and has been planted for erosion control on another 300,000 ha (2,4).

Fig. 2. Chinese Loess regions planted with thousands of hectares of seaberry shrubs to control soil erosion (2,4).

Used hundreds of years as animal fodder, seaberry was thought by legend to benefit horse health, conveying a shiny coat. This apparently led to its botanical name, Hippophae rhamnoides L. (“horse that shines”), assigned by Carolus Linnaeus in 1753 in his taxonomy monograph, Species Plantarum. Seaberry has been used for centuries in traditional Asian medicine in jam, juice, tea, liquor, skin cream or liniment (2-5). Discussed further below, seaberry's greatest value to humans are possibly the seed and pulp oils containing an extraordinary profile of essential fatty acids not replicated similarly among edible plants.

A shrub reaching 2–4 m in height in natural habitats and bearing yellow or orange-red berries (color varying among cultivars), it is sometimes called “Siberian pineapple” in Russia for its sour taste and juiciness (2). Seaberry withstands extreme temperatures from –43° to 40°C and high altitudes (up to 14,000 feet), is drought resistant and develops a pervasive root system making it valued for land reclamation, wildlife habitat, windbreaks and nitrogen-fixing ability (2,4). Possibly, its adaptation under stress to harsh growing environments contributes to its phytochemical richness.

These growing characteristics emphasize seaberry's promise as a cash crop in North America and Europe – seaberry succeeds even on relatively sterile soils, is winter-hardy while productive in annual fruit output, indicating a crop that could be successfully cultivated or grown for wildlife habitat on marginal lands in any temperate zone (2). Fruit production can be as high as 30 tons per hectare (A. Wähling personal communication).

Recently, seaberry cultivation was attempted in Western Canadian provinces and Ontario using horticultural strategies to improve yield, thornlessness, fruit size, quality, and early maturity. Mechanical harvesting and crop management techniques including soil fertility, pruning, pest, disease and weed controls were devised to promote successful crops (2).

However, these crops did not prosper mainly due to harvest difficulties caused by thorns and berry persistence to branches lacking an abscission layer that eases picking (effective mechanical harvesters are in use in Europe, A. Wähling, personal communication). The labor cost alone for harvesting a Canadian seaberry orchard was estimated to be nearly 60% the total cost of production, too high to be economically viable (2). In China, peasant laborers hand-pick seaberries at low wages allowing crop profitability for landowners, brokers and processors.

Postharvest handling and storage. Seaberries tend to have a musky odor detectable from a distance even still on the bush, with rancid taste when overripe from their oxidizable high fat and acid contents. To avoid this problem, berries must be harvested at the correct stage of maturation, quickly processed, and cooled immediately to 4°C. Alternately, many harvests are conducted only after several days of freezing temperatures which facilitate removal of berries from the branches and somewhat neutralize the acid flavor tones (2).

Color, vitamin C and E content, essential oil composition, phytosterol content and phenolic concentrations all vary according both to maturation stage of fruit, genotype across geographic regions and postharvest handling (2, 6-10).

If prepared for storage, fresh berries would ideally be individually quick frozen (IQF) to maintain nutrient and oil quality. Juice obtained by pressing or centrifugal techniques is pasteurized, stored under refrigeration or frozen for long term storage. Shelf life even of pasteurized seaberry materials is limited due to the high fat levels, but improved by refrigeration (2).

Essential Dietary Nutrients

Seaberry's botanical family, Elaeagnaceae, is within order Rosales notable by flowering plants with nutritious fruits such as strawberries, Rubus berries, apples, plums and almonds (1-3). Botanically, therefore, seaberry is in good company as a nutrient source.

Seaberry micronutrients include an impressive list of essential dietary minerals and vitamins (2-4,11). In Table 1 below are five essential minerals whose contents per serving are “good” to “excellent” percentages of the Daily Reference Intake (DRI, US National Academy of Sciences, Institute of Medicine).

Vitamin C. Exceptional is the content of vitamin C, giving seaberry unique value as a rare high-density source both of major water-soluble (vitamin C) and fat-soluble (E) antioxidant vitamins. An average of 6 different research analyses, the vitamin C content at 695 mg per 100 g is one of the highest levels reported for any plant food (2-4,11). Even at the lower levels published, 100-200 mg per 100 g, seaberry's vitamin C content per 100 g serving exceeds the DRI and is a multiple of values for goji (wolfberry, Lycium barbarum L.), cranberry (Vaccinium macrocarpon L.) or spinach (Spinacia oleracea L.) (Tables 1,3). Seaberry content of vitamin C is so extraordinary that about 75% of the total berry antioxidant capacity may come just from this one antioxidant vitamin (2).

Several authors have speculated about the wide variation of reported vitamin C in seaberries across growing regions and soils, subspecies, cultivation or postharvest handling. As with any processed fruit, all these factors potentially affect vitamin C content, contributing to differences in published values.

Tocopherols (vitamin E group). Alpha-, beta-, gamma-, and delta-tocopherols make up 95% of total tocopherols and tocotrienols in seaberry seeds, and alpha-tocopherol alone is about 83% of the total vitamin E content in berry pulp (12). Total contents of tocopherols and tocotrienols varied between 8-32 and 6-14 mg per 100 g in seeds and whole berries, respectively, demonstrating a highly enriched fruit source of vitamin E. By comparison, oils from olives, peanuts or walnuts contain about 12-20 mg vitamin E per 100 g (Wikipedia) and vitamin E content in goji, cranberry or spinach is only a fraction of the rich levels in seaberry (Table 2).

Vitamin E content varies depending on whether derived from seed oil (up to 93 mg per 100 g seeds), juice oil (216 mg per 100 g berries), or pomace after juice and seeds are removed (481 mg per 100 g berries) (11,12). By these data, seaberry appears to be one of Nature's richest fruit sources of vitamin E (Table 3), related most likely to the unusual fat content of seaberry pulp (Oils, below).

Table 1. Nutrient comparison among 3 berries and spinach

Values are mg per 100 g for whole berries. Seaberry values for nutrients in seed oil differ (see text and Table 2).

Table References

* Seaberry: references 2,3,11,12
* DRI: Daily Reference Intake in total mg; “x”, no values established.
http://fnic.nal.usda.gov/nal_display/index.php?info_center=4&tax_level=2&tax_subject=256&topic_id=1342&placement_default=0
* Goji: Gross PM, Zhang X, Zhang R (2006). Wolfberry: Nature's Bounty of Nutrition & Health, Charleston, South Carolina, United States: BookSurge Publishing ISBN 1419620487; chap. 3
* Cranberry: http://whfoods.com/genpage.php?tname=nutrientprofile&dbid=172
* Spinach: http://whfoods.com/genpage.php?tname=nutrientprofile&dbid=16

Comments on the table. Micronutrient values for seaberry are compared with 1) those of another nutrient-rich berry of Asian origin – goji, 2) a North American berry with substantial research and a France-approved health claim for antibacterial activity – cranberry, and 3) a common leaf vegetable recognized by many as one of Nature's healthiest foods – spinach. All the micronutrient levels shown for seaberry would classify as “good” to “excellent” percentages of the DRI. By comparison with the other berries and spinach, seaberry is especially enriched with iron, manganese, vitamin C and vitamin E.

Although some published statements claim that seaberry contains “over 190 bioactive compounds”, no verifiable reference showing this list could be found.

Antioxidant phytochemicals – Two classes of pigments

Those who have handled fresh seaberries or powders know this fruit for its strong pigmentation called “sea buckthorn yellow” (2,3) which readily and stubbornly stains clothing and skin. Extracted from pomace after juicing or from centrifuged sediment, the residue may be spray-dried to yield a yellow powder. To date, however, despite promise as a unique avid dye, there seems to be no common industrial use of sea buckthorn yellow. The phenolic and carotenoid contents alone may be sufficiently economical for pigment extractions from the abundant Asian crops.

Carotenoids. A characteristic carotenoid source by its bright orange-red-yellow fruit, reports for seaberry carotenes and xanthophylls are very high -- in seeds up to 85 mg per 100 g and skin/pulp as high as 2 g per 100 g (2,3,11). Carotenoids distinguish seaberry pulp oil with an orange-red pigmentation that readily stains. These contents exceed those of carotenoid-enriched goji and spinach by many times (Table 1), and are about 100 times the total carotenoid content of a carrot. Seaberry carotenoids identified (2,4):

Predicted by the variety of orange-red-yellow color of different species of seaberry, quantitative carotenoid contents vary according to species or cultivar as well as differences in postharvest processing (13).

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Author Profile

Paul M. Gross, PhD received his doctorate in physiology from the University of Glasgow, Scotland and was trained in neuroscience at the Laboratory of Cerebral Metabolism, National Institutes of Health, Bethesda, MD. A Research Scholar for the Heart and Stroke Foundation of Ontario, he published 85 peer-reviewed journal reports and book chapters over a 25 year career in medical science, and was recipient of the Karger Memorial Award, Switzerland, for publications on brain capillaries. Dr. Gross is publisher of The Berry Doctor's Journal, http://berrydoctor.com where readers can obtain free information on berry science and nutrition. He is coauthor of a book on the goji berry with X. Zhang and R. Zhang, Wolfberry: Nature's Bounty of Nutrition and Health, 2006, Booksurge Publishing (Amazon.com).