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As South Africans increasingly find themselves disconnected from their food, land, and identity, indigenous food activist Loubie Rusch is building local awareness of Indigenous foods of the Cape Floristic Region (CFR). The CFR is a diverse foodscape of more than 10,000 plant species, a quarter of which are threatened by modern agriculture and urbanization.
CFR’s current agricultural model prioritizes foods that are not native to the land, requiring increased inputs like synthetic fertilizers and water. Rooibos and vineyards are grown in monoculture, destroying smaller native plants. Drought threatens the CFR’s fragile food system.
CFR’s native foods are resilient, adapted to our annual droughts and nutrient-poor soils of the Western Cape. Studies show many native plants desalinate soil and sequester carbon more successfully than others. This is an absurdly untapped resource, considering drought and soil salinization are the most important factors limiting modern agriculture.
Foraging as in pre-colonial times would not sustain the CFR’s landscapes today; the very reason Rusch is bringing these foods into agricultural cultivation. Her recently published book, Cape Wild Foods: A Growers Guide, describes this journey and provides knowledge that is missing for both farmers and chefs interested in reawakening these foods.
Mesembryanthemum crystallinum, or ice plant, is an annual succulent native to Africa (specifically the Western Cape and Nambian desert), Asia, and Southern Europe. It is naturalized in the southwestern US, the Pacific coast of Mexico and Chile, South America, and Western Australia. M crystallinum L. is a rare vegetable for its high tolerance to drought and salinity and can complete its life cycle in soil containing NaCl at a concentration equivalent to that of seawater. The plant is covered with large, glistening cells and water vesicles, reflected in its common name of ice plant or crystalline ice plant. It is found on a wide range of soil types, from well-drained sandy soil (including sand dunes) to loamy and clay soil.
Like many salt-tolerant plants, M. crystallinum accumulates salt throughout its life in a gradient from the roots to the shoots, with the highest concentration stored in epidermal bladder cells. The salt is released when the plant dies. This results in a detrimental osmotic environment, preventing the growth of non-salt-tolerant species while allowing M. crystallinum seeds to germinate. Therefore, it is important to harvest it before it wilts and dies.
The ice plant’s leaves are edible, as with some other members of the family Aizoaceae. In southern Africa, the leaves and stems are gathered and pickled. Ice plants are also used in South Africa as a way of deterring fires, or “firescaping” gardens. The crushed leaves can be used as a soap substitute and have some medicinal uses. It is also cultivated ornamentally.
It has been shown that plants of this species grew best under moderately saline conditions. Due to its salt accumulation, M. crystallinum may be useful for bio-remediation.
Mesembryanthemum crystallinum is a new, functional food. Functional foods are “natural or processed foods that contain biologically-active compounds, which, in defined, effective, non-toxic amounts, provide a clinically proven and documented health benefit utilizing specific biomarkers, to promote optimal health and reduce the risk of chronic/viral diseases and manage their symptoms.” (Functional Food Center, FFC). The stressed plants of M. crystallinum have high concentrations of polyphenols such proline and polyols like myo-inositol, pinitol, and ononitol, which are known to have health-promoting and/or disease-preventing functions, like controlling blood glucose levels.
Myo-inositol has been used for medical purposes such as treatment for liver disease, depression, panic disorder, diabetic neuropathy, and respiratory distress syndrome.
Proline is a non-essential amino acid involved in the production of collagen and wound healing, and is a precursor of hydroxyproline which functions to maintain and heal cartilage, strengthen joints, tendons, and muscles.
Ice plant’s advantage as a functional food is that polyols can be taken from its raw tissues without processing. Other high polyol-containing foods such as beans need to be cooked, but the benefits of the ice plant can be accessed raw. This species has been utilized as a vegetable in some European countries as a quickly-cooked vegetable used to flavor green salads. In Germany, it is sold in delicatessen shops. It is a perishable product and thus its shelf life is short: only two to three days.
The species Mesembryanthemum crystallinum is also characterized by the presence of antioxidant enzymes such as ascorbate peroxidase, superoxide dis-mutase, and catalase. Historically, physicians used ice plant leaf juice to soothe inflammation of the mucous membranes in the respiratory or urinary system. In Europe, its juice has been used to treat water retention, painful urination, lung inflammation.
The use of traditional medicine is widespread and plants still present a large source of natural antioxidants that could serve as leads for the development of novel drugs. Studies confirm that M. crystallinum is resistant to insects, fungus, bacteria, and viral disease. Due to the resistance that pathogens build against antibiotics, there is a great interest in the search for new antimicrobial drugs from organisms like the ice plant.
Desertification,irrigation water constraints, and high evaporation increase soil salinization in the Western Cape. Hence, intensified use of halo-tolerant crop plants will be necessary. Plant breeding and genetic engineering programs take years to develop stable solutions. Therefore, it is important to begin the immediate cultivation of this rare leafy vegetable species.
Colonization and apartheid disrupted the connections that people held with Indigenous landscapes, decoupling our society from the native foods that once fed and healed us. To restore the food system’s balance and heal the relationship between people and place, Loubie guides us along the thousands of kilometers of coastline and biodiversity that are the South African landscape. Her research and efforts to reawaken Indigenous foods like the ice plant are paramount to sustaining the health of our communities into the future.
Nearly half of human greenhouse gas emissions are caused by agriculture. Biodiversity is the key to any regenerative farming practice as it increases farmers' resilience to climate and economic shocks. Diverse crops help carbon sequestration and climate adaptation.
The process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture.
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