Assessing the Possible Influence of Residues of Ractopamine, a Livestock Feed Additive, in Meat on Alzheimer Disease

Abstract

The feed additive ractopamine, a β-adrenergic agonist, has been approved for use in livestock for nearly 2 decades. Studies of its possible adverse effects in humans have concentrated exclusively on cardiovascular disease and cardiovascular functional disorders in the past. In this article, whether and how ractopamine may affect neurodegeneration, either to promote or to reduce the incidence of Alz­heimer disease, will be discussed based on the recent controversial findings that β-adrenoreceptor activation not only can stimulate Alzheimer-pathogenic amyloid-β accumulation but also are able to enhance hippocampal neurogenesis and ameliorate mouse memory deficits in independent laboratory studies. Furthermore, environmental enrichment has been found to prevent impairment of memory-related hippocampal long-term potentiation and microglia-mediated neuroinflammation induced by amyloid-β. These beneficial effects are achieved mainly through enhanced β-adrenergic signaling and can be imitated by β agonist isoprotenerol. Finally, it has been demonstrated that the β-adrenergic agonist salbutamol could bind directly to tau protein and interfere with the tau filament formation seen in the prodromal phase of Alzheimer disease. These complex but interesting issues lead to contradictory speculations of possible effects of ractopamine residue in meat on Alzheimer disease. Hypotheses derived from this review surely deserve carefully designed laboratory investigations and clinical studies in the future.

Ractopamine residues in meat might reduce the risk of type 2 diabetes

“…, 2014). Additionally, there were also concerns about assumptive enhancing effects of ractopamine on the development of Alzheimer disease (Fan, 2021) and tumour growth (Fan, 2022). Therefore, comparative large-scale epidemiologic studies are warranted, peculiarly between countries where ractopamine is used as a feed additive and countries where ractopamine is prohibited, to see whether the potential improvement of glucose metabolism resulting from trace ractopamine residues in meat could really benefit human health in a long-term way.…”

“…Despite carcinogenicity and genotoxicity could be excluded with acceptable daily intakes on recommended maximal residue limits of ractopamine in animal food (Scientific Opinion of the Panel on Additives and Products or Substances used in Animal Feed, 2009), the risk of cardiovascular functional disorders and cardiovascular diseases was considered to be dose-dependent for ractopamine in human models and thus not acceptable in certain countries (Zaitseva et al, 2014). Additionally, there were also concerns about assumptive enhancing effects of ractopamine on the development of Alzheimer disease (Fan, 2021) and tumour growth (Fan, 2022). Therefore, comparative large-scale epidemiologic studies are warranted, peculiarly between countries where ractopamine is used as a feed additive and countries where ractopamine is prohibited, to see whether the potential improvement of glucose metabolism resulting from trace ractopamine residues in meat could really benefit human health in a long-term way.…”

“…It's influence on glucose homeostasis could also be estimated based on its nature as a β-adrenergic receptor agonist. Recently published research reports showed that acute treatment with β-adrenoceptor agonists was able to stimulate glucose uptake into brown adipose tissue, increase body energy expenditure, and improve metabolic health in rodents without the need of activating insulin downstream effectors (Olsen et al, 2019), while chronic feeding of β-adrenoceptor agonists could stimulate glucose uptake in skeletal muscle, improve insulin resistance and glucose homeostasis in diet-induced obese mice (Kalinovich et al, 2020; van Beek et al, 2021). On the other hand, in β2-adrenoceptor knockout mice fed on high-fat diet, significant fasting hyperglycemia persisted despite concurrent hyperinsulinemia (Fernandes et al, 2014).…”

Capture-SELEX: Selection Strategy, Aptamer Identification, and Biosensing Application

“…Ractopamine (RAC) is a -adrenergic agonist used illegally as an animal feed additive for increasing skeletal muscle mass, reducing fat deposition, and increasing protein accretion in livestock [ 125 , 126 ]. The accumulation of RAC in animals may increase the risk of food poisoning in humans and have other adverse effects on human health, such as causing headache, tachycardia, and muscle tremors [ 127 ].…”

Ractopamine at the Center of Decades-Long Scientific and Legal Disputes: A Lesson on Benefits, Safety Issues, and Conflicts

“…Catecholamines (CAs) are a group of organic compounds consisting of a hydroxyl group and an amine side chain. Most CAs are used by dopamine, norepinephrine, and epinephrine receptors in the nervous system [ 49 , 50 ]. CAs have received the attention of researchers because of their early recognized involvement in different neurological disorders [ 51 ].…”