Annatto – a natural food color with many health benefits

 

    Annatto is a natural orange-red food colorant obtained from the seeds of the achiote tree (Bixa orellan). It has been widely used by the food color industry. Annatto contains a mixture of carotenoids, which includes bixin and norbixin. Bixin is the oil-soluble form of annatto, the primary pigment surrounding the seeds in the fruit of the plant. Bixin can be turned into norbixin, which is water-soluble. Annatto is widely used in many processed foods, especially dairy products. It is the ingredient used to dye cheese bright yellow, orange or bright red.

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    Bixin and norbixin belong to the same carotenoids family which includes many well-known colorful plant pigments like beta-carotene in carrots. The carotenoids include many plant pigments that can only be synthesized by plants not humans, and they are responsible for scavenging free radicals and thus act as antioxidants. Many research papers have reported various health benefits of annatto/bixin/norbixin.

 

    Norbixin was found to protect cells against DNA damage induced by UV radiation, hydrogen peroxide, and superoxide anions, all known DNA damage causes. Norbixin enhanced cell survival at least 10 times. The SOS induction by UV radiation was inhibited 2.3 times more when cells were grown in the presence of norbixin. Norbixin also has antimutagenic properties, with a maximum inhibition of hydrogen peroxide-induced mutagenic activity of 87% (1).

 

    Mercury exposure can lead to neurotoxic effects, damage to the immune and cardiovascular system, and causes DNA-damage and cancer. Both bixin and norbixin exert protective effects against mercury-induced DNA damage. Rats were treated either with methylmercury, bixin, norbixin, or combinations of the metal compound and the pigments consecutively for 45 days. Treatment with the metal alone caused a decrease in the glutathione levels (GSH, an antioxidant) (35%) and induced DNA damage in the liver and blood cells. When bixin or norbixin was given in combination with organic mercury, the highest concentrations of the carotenoids (10 mg/kg/bw/day bixin and 1 mg/kg/bw/day norbixin) protected against DNA-damage (reduce 44%-49%). With both of them, a moderate increase in the GSH levels in both metal-treated and untreated animals. Consumption of bixin and norbixin may protect humans against the adverse health effects caused by exposure to mercury (2).

 

    The immune system is especially vulnerable to oxidative damage because many immune cells, such as neutrophils, produce reactive oxygen (ROS) and nitrogen oxide as part of the body's defense mechanisms to destroy invading pathogens. The function of neutrophils is altered in diabetes. In diabetes, the excess generation of highly reactive free radicals, which is largely due to hyperglycemia, causes oxidative stress, further accelerating the development and progress of the disease and its complications.

 

    Rodent studies showed that neutrophils from diabetic animals produced significantly more ROS and nitric oxide than their respective controls. Supplementation with 0.1% of beta-carotene or annatto (2.17 g of bixin per 100 g annatto extract) for 7 days was able to dramatically reduce the production of the ROS in the neutrophils of diabetic rats (3), and for 30 days was able to reduce both ROS and nitrogen oxide (4). Annatto extract may have therapeutic potential for reducing oxidative stress and protect immune cells in diabetes.

 

    Bixin was found to stimulate immune response and exerted anti-inflammatory (reduced C-reactive protein) as well as anti-oxidative (reduced 8-OHdG, a DNA damage marker) effects after 16 weeks of supplementation at either 5, 10 or 20 mg per day doses in dogs. Natural killer cell killing efficiency was significantly enhanced (p < 0.05) at week 6 in the 10 mg/day treatment group compared with the control treatment group at an effector: target ratio of 10:1 (5).

 

    Norbixin was one of the 41 effective food additives from the screened 145 food additives approved in Japan that were found with enhanced efficacy of the split influenza hemagglutinin (HA) vaccine against lethal virus attacks in a mouse model (6).  That means that if a person gets exposed to the virus, these food components may better protect the person from detrimental damages from the viral infection such as the extreme case, death.

 

    Evidence has shown that antioxidants preserve an adequate function of immune cells against homeostatic disturbances caused by oxidative stress. Because the immune system is an indicator of health and a predictor of longevity, the protection of this system afforded by dietary antioxidant supplementation may play an important role to achieve health. Carotenoids are phytochemicals considered beneficial in the prevention of a variety of major diseases. Evidence has suggested that the action of carotenoids on immunity and diseases may be mediated, at least in part, by their ability to quench ROS.

 

    In diet-induced obese mice, bixin treatment suppressed the development of hyperlipidemia and hepatic fat accumulation. In the livers of bixin-fed mice, the mRNA levels of PPARα target genes related to fatty acid oxidation were up-regulated. Bixin treatment also improved obesity-induced dysfunctions of carbohydrate metabolism, such as hyperglycemia, and hyperinsulinemia. Serum triacylglyceride concentrations were significantly decreased in the bixin-fed mice (a 24% decrease in 1% bixin-fed mice compared with the control mice). The addition of 1% bixin in the diet decreased the serum glucose and insulin levels by 22 and 32%, respectively, compared with those of control mice. These results indicated that bixin can be useful for the management of metabolic dysfunctions in diet-induced obesity and later developed diabetic conditions (7).

 

    To evaluate the effect of annatto carotenoids intake in a single high-calorie meal (a hamburger and a 350 ml soft drink, ~1/2 daily caloric intake of an adult person) on postprandial biochemical, inflammatory and oxidative stress markers, 12 young healthy volunteers were included in a randomized, controlled crossover study. After baseline fasting blood samples were collected, subjects received one of the 3 meal options: high-calorie meal without carotenoid (placebo) or containing 1.2 mg/kg bixin or 0.06 mg/kg norbixin. The intake of annatto carotenoids associated with a high-calorie meal did not change the postprandial levels of glucose or insulin. However, norbixin intake reduced the postprandial levels of inflammatory cytokines (IL-1, IL-6, and TNF-α) and lipid oxidation 60-120 minutes after the meal. Bixin only partially prevented postprandial-induced lipid oxidation. Results indicated that the intake of these annatto carotenoids may help to reduce the postprandial inflammatory and oxidative stress responses to high-calorie meals (8), but one-meal is perhaps too short a treatment to see any other effects on glucose, insulin or lipid levels as shown in long-term diet-induced obesity rat study (7).

 

    The accumulation of N-retinylidene-N-retinylethanolamine (A2E, a toxic by-product of the visual pigment cycle) in the retinal pigment epithelium (RPE) is a major cause of visual impairment in the elderly. Photo-oxidation of A2E results in retinal pigment epithelium degeneration and followed by vision loss. Norbixin was evaluated in retinal pigment epithelium cells challenged with A2E and illuminated with blue light, and it provided an improved photo-protection as compared with lutein or zeaxanthin. In a mice model of age-related macular degeneration (AMD), intravitreally-injected norbixin maintained the electroretinogram and protected photoreceptors against light damage. In a standard rat blue-light model of photo-damage, norbixin was at least equally as active as phenyl-N-tert-butylnitrone, a free radical spin-trap. Mice of the AMD model were treated orally for 3 months with norbixin that showed a reduced A2E accumulation in the retina. Norbixin is rapidly and efficiently absorbed due to its water-soluble feature that can be promising as an oral treatment for the leading vision loss disease macular degeneration (9).

 

    While we may be against artificial colors added into the processed foods we find on the market, the natural food color annatto/bixin/norbixin may be a color that we actually would like to see more in our diet. These carotenoids offer many health benefits such as anti-oxidative, anti-inflammatory, and immune-boosting.  They can protect cells/animals against common known environmental oxidative stress causes, and help reduce known elevated oxidative stress like obesity and diabetics. They can stimulate immune responses, protect the animals from a lethal dose of viral infection, and even protect eye cells from degeneration from light damage. Annatto can be a functional food color as part of nutritional foods.

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References:

1. Júnior AC, Asad LM, Oliveira EB, Kovary K, Asad NR, Felzenszwalb I. Antigenotoxic and antimutagenic potential of an annatto pigment (norbixin) against oxidative stress. Genet Mol Res. 2005. 31;4(1):94-9.

2. Barcelos GR, Grotto D, Serpeloni JM, Aissa AF, Antunes LM, Knasmüller S, Barbosa F Jr. Bixin and norbixin protect against DNA-damage and alterations of redox status induced by methylmercury exposure in vivo. Environ Mol Mutagen. 2012. 53(7):535-41.

3. Rossoni Júnior JV, Araújo GR, Pádua Bda C, Magalhães CL, Chaves MM, Pedrosa ML, Silva ME, Costa DC. Annatto extract and β-carotene enhances antioxidant status and regulate gene expression in neutrophils of diabetic rats. Free Radic Res. 2012. 46(3):329-38.

4. Rossoni-Júnior JV, Araújo GR, Pádua Bda C, Chaves MM, Pedrosa ML, Silva ME, Costa DC. Annato extract and β-carotene modulate the production of reactive oxygen species/nitric oxide in neutrophils from diabetic rats. J Clin Biochem Nutr. 2012. 50(3):177-83.

5. Park JS, Mathison BD, Chew BP. Uptake and immunomodulatory role of bixin in dogs. J Anim Sci. 2016. 94(1):135-43.

6. Feng H, Yamashita M, Wu L, Jose da Silva Lopes T, Watanabe T, Kawaoka Y. Food Additives as Novel Influenza Vaccine Adjuvants. Vaccines (Basel). 2019. 7(4). pii: E127.

7. Goto T, Takahashi N, Kato S, Kim YI, Kusudo T, Taimatsu A, Egawa K, Kang MS, Hiramatsu T, Sakamoto T, Uemura T, Hirai S, Kobayashi M, Horio F, Kawada T. Bixin activates PPARα and improves obesity-induced abnormalities of carbohydrate and lipid metabolism in mice. J Agric Food Chem. 2012. 60(48):11952.

8. Roehrs M, Conte L, da Silva DT, Duarte T, Maurer LH, de Carvalho JAM, Moresco RN, Somacal S, Emanuelli T. Annatto carotenoids attenuate oxidative stress and inflammatory response after high-calorie meal in healthy subjects. Food Res Int. 2017. 100(Pt 1):771-779.

9. Fontaine V, Monteiro E, Brazhnikova E, Lesage L, Balducci C, Guibout L, Feraille L, Elena PP, Sahel JA, Veillet S, Lafont R. Norbixin Protects Retinal Pigmented Epithelium Cells and Photoreceptors against A2E-Mediated Phototoxicity In Vitro and In Vivo. PLoS One. 2016. 11(12):e0167793.